Solving system of quadratic equations using substitution

This quick video covers how to solve a system of quadratic equations using the substitution method.
Step by step directions are given.

For more videos see:
MooMooMath

For more on Quadratic Equations see
Analytical Geometry

Apothem of a triangle

Video of the Day



What is the apothem of a triangle?

The apothem is the distance from the center of an equilateral triangle to the side.

This video finds the apothem of a equilateral triangle with sides of 12 units.

For more about Equilateral Triangles see

Equilateral Triangles/MooMooMath

Volume of a Cone and a Cylinder

Today's video reviews how to find the volume of a cone and a cylinder.
The cone video tackles finding the volume given the slant height and not the cone height. You can use the slant height with the Pythagorean Theorem to find the height,which you can plug into the slant height formula.

The cylinder video gives step by step directions for finding the volume of a cylinder.

For more on volume of a cone see:
Volume of a Cone

Volume of a Cylinder

Video of the Day " Isosceles Triangle"

Today we have three videos that cover properties of an isosceles triangle. An isosceles triangle is a triangle with two congruent angles and sides.

Video one answers the vertex angle sample problems

Video two reviews how to find the base length of an isosceles triangle

Video Three gives directions on how to find the side length of an isosceles triangle

For more on isosceles triangles see:
MooMooMath/Isosceles Triangles

Video of the Day " Triangle Inequalities"

 What makes a triangle actually a triangle? The video demonstrates what defines a triangle.

Transcript
Triangle Inequalities
Hi Welcome to MooMooMath. Today we are going to talk about proportions of a triangles or what happens to the sides that create a triangle. So the best method for me to show you how this works is actually have some straws to show you how triangles work. The first straw is 8 inches long, the second straw is 6 inches long, and then I have some 4's and some 2's. I'm going to draw you some different combinations of triangles. I will show you with the straws which make triangles and which do not.  O if I have the side length of 8 and I pair this with a side length of 4 and a side of 6. Those three pieces can create a triangle. So the bottom one what happens if I replace the side of 4 with a side of only two?  Look what is going to happen. Can I create a triangle? Well guess what, it doesn't reach. They actually are the same length because this side is 8 and this side is 2, and this one is 6, and it's not large enough to reach to the end. So an 8, 6, and 2 don't work. So what happens if I try a 6 and two 2's? OK here is a side of 6 and here is a 2 and here is a 2. Notice how they can't reach each other. So what are the rules for creating triangles? So let's look at the rules. The rules say the two shorter sides have to add up to or be greater than the length of the longer side. So in the first one worked. It was 8, 6, and 4. So 6 and 4 was 10 which is greater than the longer side of 8. So here is another example. If you have a side of 2 and a side of 4 they add up to a number greater than the longest side of 5 so it is a triangle. If this side is 8 and this side is 6 the side of 4 that one works. So let's write the inequality that actually goes with that to represent that it works. So we have a side of 4 inches and a smaller side of 6 inches and they add up to a side greater than 6 inches. Yet the side that was 2 and another of 2 does not add up to a number greater than side that was 6 so this one doesn't work. So the 2 small sides have to add up to be equal or greater than the longer side. Hope this was helpful.

For more on triangle inequalities and an infographic please see MooMooMath/Triangle Inequalities

Video of the Day " Similar Triangles"

What are similar triangles? Similar triangles are triangles in which the only difference is size. Similar triangles have corresponding sides that have the same ratio and equal angles.

Video Guide
0:15 Definition Similar Triangles
1:04 Rules for solving similar triangles explained  
       Set up a proportion then solve the proportion
1:37 Sample problem similar triangles solved with step by step directions
2:45 Sample problem finding missing sides on similar triangles with step by step directions

For more information see MooMoo Math Similar Triangles

Video of the Day " How to divide and multiply radicals"

How to divide and multiply radicals

In this video you will .....

Learn how to add radicals

Learn how to multiply radicals

Simplify square roots

Learn how to divide radicals

For six more videos on radicals please see: MooMooMath/Radicals

Video of the Day " Are these lines perpendicular?"

"Are these lines perpendicular?"

Given points how do you determine if the lines created from ordered pairs are penpendicular or not.
Review: Lines are perpendicular if the slopes are negative reciprocals or multiply to -1
Step 1. Use the slope equation to calculate the slope from the ordered pairs.
Step 2. Look at the slope from each line and see if they are a negative reciprocal or if you multiply the two slopes together it equals -1

For more on perpendicular lines see MooMooMath/Perpendicular Lines

Video of the Day " What is a Rhombus?"

What are the properties of a rhombus? A rhombus has four congruent sides, opposite angles that are congruent, and when the diagonals of a rhombus bisect they form four right angles.
MooMooMath/Rhombus

Transcript

What is a Rhombus?

Hi welcome to MooMooMath. Today we are going to look at the properties of a Rhombus. I have drawn a figure that looks like a Rhombus. We have DOGS and a rhombus falls in the quadrilateral family as a parallelogram. So we have quadrilaterals then a smaller sub of parallelograms with rectangles over here and rhombuses over here and these two (rectangles and rhombuses) are not the same. Since a rhombus is a parallelogram it does have all the properties of a parallelogram. So it has opposite sides O and G and D and S that are congruent and they are also parallel and the OG and SD are also parallel. What sets a rhombus apart that not only are the opposite sides congruent (equal) top to bottom, left to right all four are congruent. So this side is 5, this side is 5, all four sides are a 5 so that is why I call it a squished square  So we have opposite sides that are congruent, opposite angles that are congruent, OS and DG are opposite angles. We have parallel sides and we can have the angles being supplementary. D and O are supplementary and O and G are supplementary. Now what sets the rhombus apart besides these four sides being congruent is it has some properties with the diagonals. I will draw OS and DG and one property is that the diagonals are perpendicular. They cross and make four right angles. Now what is going to happen is O to the center C, let’s call that C,and C ( the center) to S, call that S these two segments are congruent and these two segments are congruent ( points to segments D-C and C-G) and you can see you have 4 congruent triangles. So these smaller triangles are reflections and are congruent to each other. Another property is the diagonals bisect each other. Which just means they cut each other in half. So the segments are congruent. Hope this video was helpful

Video of the Day " What is a Perpendicular Line?"

What is a perpendicular line?

Quick overview of a perpendicular line.

Transcript

Perpendicular

Welcome to MooMooMath. Today we are going to look at perpendicular lines. What are perpendicular lines or what is perpendicular? Well perpendicular are two lines that intersect at 90 degree angles. So let’s look at a couple of examples of where we will see those. So we have two lines and they are intersecting at 90 degree angles, and I will label it with a little box that represents 90 degrees, and once we know this is 90 degrees we know the other three are 90 degrees because these are lines and lines have a degree of 180 so that would make all four of these 90 degrees. Now let’s look at the two line segments. This angle is 90 degrees and you will often see this in a right triangle. So a right triangle has two segments that are perpendicular and measure 90 degrees. So that is perpendicular lines. Hope this helps

For more information and examples of perpendicular lines see: MooMooMath/Perpendicular Lines

Video of the Day " Measuring angles with a Protractor"

Protractors are used to measure angles. Today's video gives step by step directions for using a protrator to measure an angle
For more information and a nice applet to practice measuring angles with a protractor see: MooMooMath/Protractor

Video of the Day " Absolute Value Inequalities"

Today's video reviews how to solve absolute value inequalities. The video gives step by step directions for solving |3x – 5| ≥ 4

A quick overview of solving absolute value inequalities is as follows:

• Set up two cases
• Rewrite without the absolute value bar
• Solve the inequalities
• Place on a number line

Solve

|3x – 5| ≥ 4

For more information on Absolute Value Inequalities see:

MooMooMath Absolute Value Inequalities

Video of the Day " Trigonometry Unit"

If you need help in trigonometry I have put together a trigonometry unit. This is one video of the trigonometric unit that contains 14 videos, along with a note taking guide for each video, Click here for the table of contents: Trig Unit

Video Guide
0:30 Definition of the trig ratios
2:42 Learning how to use the trig functions
Reviewing the steps
1.  Find the reference angle.
2. Label OPPOSITE, ADJACENT, HYPOTENUSE
3. Which two do you have?  Which function is it?
4. Set up the ratio
5. Solve it!
5:11 Practice problem 1 Deciding the functions
6:30 Practice 2 Find opposite side using tangent
7:45 Practice problem 3 Using cosine
9:53 Solving Tan 52/1 = x/12
12:33 Solving Sin 48/1=x/17
13:39 Solving Tan72/1 = x/34
15:03 Solving Cosine 25/1  = 7/x
17:22 Reviewing using trig functions

Video of the Day " Finding the Area of an Isosceles Triangle"

Finding the area of a triangle of an isosceles triangle. The formula for area of a triangle is 1/2 base times height.

Step 1. Determine your base
Step 2. Find the altitude
Step 3. You can find the height by creating a right triangle by drawing a line from your vertex.
Step 4. Use the Pythagorean Theorem to determine the missing leg of the right triangle which will be your height.
Step 5. Plug the altitude (height) into 1/2base x height

For more information on area of triangle see
http://www.moomoomath.com/Finding-the-area-of-a-triangle.html#.Ul861VCsiSo

Video of the Day "Solving Equations"

Today I'm including several videos that solve equations.
List of equations solved.

Equations containing radicals

Equations containing absolute values

Quadratic Equations

Equations in volving rationals

How to Simplify Radicals Video

Equations with Absolute Values

Quadratic Equations

Equations involving a rational

For sample problems and more information see
MooMooMath/Equations

Video of the Day " Reducing a Fraction"

Reducing Fractions
Hello welcome to MooMooMath. Today we are going to talk about how to reduce fractions and I'm going to show you two methods. There is a second video that goes over a different method of reducing fractions. So pick the one you like best. So let's start with twenty four over thirty six. I know that both of those numbers are divisible by two. Let's reduce to this ( twelve over eighteen) I can reduce again, I notice there is another common factor so I reduce again and reduce it all the way down to two thirds. So that is method one where you are looking for common factors. So what method did I use? The first step is to find any common factor, and just start factoring or reducing by dividing the numerator and the denominator by that factor, and then you try it again. You continue this until you don't have any more common factors. So let's try a second problem using the same method. I'm going to start with 108 and 144. I notice that both of those numbers are even so I'm going to start with two and divide the numerator and the denominator by two. So that gives 54 over 72. I notice I have even numbers again so I can divide by two again. When I divide by two I get 27 over 36. I notice I have common factors of three so I divide the top and bottom numbers by three and I get 9 over 12. I can then further reduce by three and end up with three fourths. So I just find a common factor and continue to reduce it down until I get the smallest form. Hope this method was helpful.

For more information on fractions see: MooMooMath/Fractions

Video of the Day "Slope of Line"

Today I have two videos posted on slope. These are very basic videos on slope,but you have to learn to walk before you can run.

Video 1
When a line has a negative slope the line slopes downward when you move from left to right. Notice that as y decreases, x increases. When a line has a negative slope the two variables move in opposite directions. Video explains and demonstrates a negative and positive slope of a line.

Video 2
What is an undefined slope and what does it look like on a graph. The video goes what a line looks like that has an undefined slope and why.

For more information and a helpful slope calculator see:  Slope Calculator

Video of the Day "Area of sector of a Circle"

How to find the area of a sector of a circle.

This video gives step by step directions for finding the area of a sector of a circle. Think of the sector of a circle as a pizza slice of a circle.
In order to find the sector area  use the formula:

Measure of the central Angle/360*pi* radius squared

For more information and an area of a sector calculator see MooMooMath/Area of Sector

Video of the Day " Trig Ratios"

This video gives you a simple step by step guide for using trig ratios in order to find missing angles or legs of a right triangle .

The trig ratios are as follows:

  

Sine Function	sin(θ)	Opposite / Hypotenuse
Cosine Function	cos(θ)	Adjacent / Hypotenuse
Tangent Function	tan(θ)	Opposite / Adjacent

For more information on trig ratios and a trig calculator

Trig Ratios/MooMooMath

Video of the Day " Solving word problems with proportions"

Step by step directions for solving Math word problems involving proportions and a video.

In order to solve word problems with proportions you first set up a proportion.

Next, set up a second ratio with the same information on the numerator and denominator.

 Finally, set these ratios equal, and then cross multiply  

I understand this doesn't involve Geometry, but I recently had some questions about this topic.

For more videos,an applet, and more example problems please see Proportion Word Problems

Video of the Day " Percent increase and decrease word problems"

This video gives directions for solving percent increase and decrease word problems:

Example percent increase word problems.

Bob bought a bike for $40, and he sold it for $60.  He made a profit of what percent?
A cell phone was reduced from $120.00 to $80.  The phone was marked down what percent?

Drew's followers on FB increased from 200 followers to 600 followers. By how much did his number of followers increase?

For more video tutorials,example problems, and a percent increase calculator please see
Percent and Decrease word problems

Video of the Day " Writing Linear Equations"

Writing Linear Equations

If given two points on a line how do you write the linear equation for the line?
Given (3,1) and (7,4) write a linear equation

Step 1 Find slope
Step 2 Plug the slope into the linear equation solve for b
You can use any pair of the given points.

Writing Linear Equations

Video of the Day Circles Unit " Angles Inside and Outside"

Circles Part 1 Lesson 8

Angles Inside and Outside
Video Guide
00:43 Central angle and arc measures defined and illustrated
01:12 Inscribed angles and angles with the vertex on the circle defined and illustrated
02:20 Definition and explanation along with an illustration of an angle inside the circle but not central
04:00 Sample problem- Finding the measure of an inside angle given two arc measures.
05:04 Angles outside a circle defined and illustrated
06:10 Formula for finding the measure angle of an angle outside the circle
07:05 Helpful hint for when to add and when to subtract the inside and outside arcs
8:27 Question 1 Find x and m angleBEC
8:50 Question2 .  Find m angleBDC
9:24 Question 3 Find the arc measure, z.
10:50 Question 4 Find the arc measure, z and m angle1.
12:20 Question 5 Given m angle ABC = 65o and m angleDFE = 25o
Find measure of arc AC, x and the measure arc DE, y.

Find the note taking guide here Circles Lesson 8


                                             

Video of the Day " Probability of Independent Events"

How to calculate the probability of independent events.

How to calculate the probability of two independent events.Independent events do not have any impact one another.
What is the probability of drawing a star from group one and an arrow from the second group.?
Calculate the probability of event one and multiply this by the probability of the second event.

For more information see Probability/MooMooMath

Video of the Day " Solving Systems of Equations by Graphing"

Solving Systems of Equations by Graphing

Step by step directions for finding a solution to a systems of equations by graphing.
Video Guide
0:10 Start with 2x + y=8 and x-y=4
0:21 Overview of the step by step directions
0:49 Solve for y for the equation  2x+y = 8
1:12 Graph this equation
1:44 Solve for y for x-y=4
2:27 Graph this equation
2:48 Discover where the two lines intersect
3:07 Solution
3:09 Check your solution by plugging the solution into the original equations

For more on Solving systems of equations see MooMooMath/systems of equations

Video of the Day " Spheres: Definition and Finding Area and Volume"

Circles Part 2 Lesson 6
Spheres

Note taking guide

Video Guide

0:09 Definition of a sphere

0:42 An example of the definition of a sphere

1:16 Radius of a sphere explained.

2:58 The great circle explained with an illustration

3:28  Definition of hemisphere and a brief explanation of hemisphere

3:49 Formula for surface area of a sphere

4:16 Formula for volume of a sphere

4:40 Sample problem with step by step instruction over how to find surface area of a sphere.with an exact answer and a rounded decimal.

6:55 Example problem with step by step instructions for finding the volume of a sphere.

Video of the Day " Finding the Surface Area of an Octagonal Prism"

How to find the surface area of an octagonal prism
Use the formula: Two times the base area + Lateral area
Step 1. In order to find the base area you will need to find the apothem using the central angle and then trig to find the apothem.
Step 2. Plug the apothem into 1/2*apothem*perimeter = base area
Step 3. Multiply the perimeter times height for the lateral area
Step 4  Add step 2 ( base area)and step 3 ( lateral area) for your surface area

Please visit our website
http://www.moomoomath.com/

Video of the Day " Rules for Dividing Exponents"

Video Guide for " Rules for Dividing Exponent

00:21 Rules for dividing exponents
00:48 Example problem dividing exponents
01:11 Example problem number 2 dividing exponents
02:22 Rules for negative exponents when dividing
02:36 Rules for dividing radicals and a sample problem
03:17 Rules for dividing rationals
04:34 Rules for dividing negative exponents with samples problems
05:40 Rules for simplifying a fourth root
06:18 Sample problem of simplifying a fourth root
07:46 Sample problem of simplifying a fourth root number 2
09:36 Rules for dividing exponents that are fractions

For many more videos covering exponents see Exponents

Video of the day " Volume of a sphere"

Step by step directions for finding the volume of a sphere
Use the formula 4/3pi radius cubed     4/3πr^3
Find the volume of a sphere with a radius of 6
Plug 6 into the formula  4/3π6^3
This gives you 288π^3  (Units of volume are cubed)

For more videos visit our You Tube Channel or MooMooMath.com

Video of the Day " Surface Area of a Hexagonal Prism"

Step by step directions for finding the surface area of a hexagonal prism.
Video Guide
00:11 Definition of a hexagonal prism
0:28 Overview of how to find the surface area
0:31 Formula for finding the area of the base of the prism
0:46 Directions for finding the lateral area
1:04 Looking at the hexagon as if it is layed out flat
1:27 Working an example problem,finding the base area first
3:18 Finding the area of the sides using perimeter times the height
3:58 Adding the base area plus the side area for the surface area

Visit or Subscribe our You Tube Channel for many more videos

Video of the Day " New MooMooMath You Tube Trailer

I finally got around to creating a new You Tube trailer for my channel. It is just a basic power point converted to a video, but I think it turned out pretty good

For a list of all my videos see A-Z Video List

Video of the Day " Congruent Triangles"

Video explains five methods for proving that triangles are congruent. The five methods for triangle congruence are
SSS Side Side Side

SAS Side Angle Side

ASA Angle Side Angle

AAS Angle Angle Side

HL Hypotenuse Leg
In addition each method has several examples and explains why the triangles are congruent along with tips and guidance from a veteran Geometry teacher.

For more information see:  Congruent Triangles

Video of the Day " Surface area of a cone"

Think of surface area of a cone as how much ice cream you can stuff in an ice cream cone Surface area of a cone explained. The surface area of a cone is found by finding the lateral area and adding this to the base area.

Surface area of a cone

Video of the Day " Perimeter of a Rectangle"

Enjoy these two videos that cover finding the perimeter of a rectangle.

For more information please see: Perimeter of a rectangle

Video of the Day " Percentage word problems"

The video gives instruction on solving the following percentage word problems:

Thirty students took a Math test. If only five of these students passed the test, what percent failed?

Drew received an 80% on his EOCT Math test. The test had 200 questions on it. How many questions did Drew get incorrect?

There are thirty students in a class. Twenty of those students are female.
What percent of the class are female?

Kate bought a new dress at 85% of the regular price.
After the discount of 85% she paid $20.00 for the dress. What was the regular price?

For more information see Percentage word problems

Video of the Day " Solving word problems using the Pythagorean Theorem"

Word problems that are solved using the pythagorean theorem.

Problem 1. A wire is stretched from the top of a 12 foot pole to a stake 5 feet from the base of the pole. How long is the wire?

Problem 2. Find the height of a parallelogram with sides of 17 units by 15 units.

For more information on solving Pythagorean word problems see:
http://www.moomoomath.com/The-pythagorean-word-problems.html

Laws of exponents

Video of the Day

Laws of Exponents

Here is a video guide that goes along with the laws of exponents.

:14 Review Laws of Exponents:

:36 Sample problem multiplying exponents

1:03 Sample problem multiplying negative exponents

1:39 Sample problem with an exponential expression raised to a power

2:15 Sample problem when you have a quantity squared

3:52 Sample problem negative exponent expression raised to a power

4:02 How to work with a negative exponent

4:19 Simplifying exponential fractions

5:05 Simplifying exponential fractions with positive and negative exponents

For many more videos on exponents please see   Exponents

4 videos over Finding the Area of a Sector of a Circle

Enjoy this slideshow of videos that cover the area of a sector.
Finding the area of a sector ( 2 videos)
Find the radius of a circle if given the sector area.
Finding the area of a sector in radians.
Hope they help and for additional information see
Area of a Sector

Area Formulas Chart Poster

This nifty poster contains perimeter and area formulas for most of the commonly used plane shapes. Enjoy If you enjoy please share or embed

<iframe width="600" height="1846" frameborder="0" scrolling="no" style="overflow-y:hidden;" src="https://magic.piktochart.com/embed/1772583-area-formula-chart"></iframe>

What is a triangle?

How do you know a triangle is a triangle. A shape must satisfy these three theorems in order to be classified as a triangle

Finding the side length of an isosceles triangle

In order to find the side length of an isosceles triangle the following formulas are used:

             a = length of legs

 b = base

  h= height

Remember an isosceles triangle has two congruent angles and two congruent sides.

The video works a sample problem in which the side length of an isosceles triangle is calculated using the above formulas.

Area of a triangle GIF

Quick GIF that covers how to find the area of a triangle if you are given the height. If the height is not given there are several methods for finding the height including Herons formula. This page reviews several methods for finding the area of a triangle based on information you are given. Area of triangle

I understand my GIF is not polished and slick. As a teacher I can't spend hours making the perfect GIF but I enjoy creating these simple little Math GIFs with a very basic program, I feel I get a descent product for the amount of time spent creating it. 

Five videos that help with SOHCAHTOA

SOHCAHTOA has been used for years in Geometry classes to help remember the trig functions. Here are five videos that do a nice job of explaining the basic trig functions.

This a very basic video but is very creative and well done.

The story of SOHCAHTOA This video is creative and really helps you remember the trig functions.

This video actually works out several problems using the trig functions. The instructor is clear and helpful .

This video is really helpful if you need some help using your TI calculator to solve trig problems.

This video reviews the basics of trig functions and SOHCAHTOA

Click here for more information on SOHCAHTOA

Congruent Triangles GIF

Five ways to prove a triangle congruent.

Please feel free to share, post, or use on your website

http://www.moomoomath.com/Proving-triangles-congruent.html

Video of the Day " Solving Absolute Value Inequalities"

Absolute value inequalities

Todays video gives step by step directions on how to solve absolute value inequalities. For more information on this topic please see " Absolute value Inequalities

Angle Side Angle

I need help with understanding " angle side angle" The following two videos explain "ASA" which can be used to prove that two triangles are congruent.

The first video covers when to use angle side angle and the second video works the angle side angle proof.

Angle Side Angle Proof

Five Methods to Prove Triangles are Congruent

This video gives an overview of five methods one can use in order to prove that triangles are congruent.

The five methods covered are as follows:

SSS Side Side Side
SAS Side Angle Side
AAS Angle Angle Side
ASA Angle Side Angle
HL Hypotenuse Leg