What's a trigonometric ratio? It is a ratio between two sides of a right triangle. In this problem, find cosine(A) in the given right triangle. Use the ratio of the adjacent side divided by the hypotenuse to find cos(A). The instructor...

There are several pieces to this problem. But luckily all the necessary pieces are here. There are five variables and three different formulas to use to get the solutions. The instructor diagrams the triangular prism and labels the...

The teacher explains how the formula for a triangle was determined. It is related to a parallelogram. What? The formula for the area of a triangle is derived from the area of a parallelogram? Seeing is believing, so watch this video to...

Use the formula for the area of a triangle to find the height of the triangle. If the problem gives the value of the area and the value of the base, then the height can be found using the formula for the area of a triangle. The...

Triangles are classified by their angle measurement as well as by the length of their sides. Here are some names that identify the types of triangles: isosceles, equilateral, scalene, obtuse, and acute. Watch this video to learn about...

Triangles are classified by their angle measurement as well as by the length of their sides. Here are some names that identify the types of triangles: right, isosceles, equilateral, scalene, obtuse, and acute. Watch this video to learn...

Triangles are classified by their angle measurement as well as by the length of their sides. Here are some names that identify the types of triangles: right, isosceles, equilateral, scalene, obtuse, and acute. Watch this video to learn...

Use the Triangle Sum Theorem to find the value of each of the inside angles of a triangle. This triangle problem has to do with the ratio of the angles to each other. Find the measure of each angle if the ratio is 1:3:8. Not sure how to...

The triangle sum theorem states that the interior angles of a triangle add up to 180 degrees. So it seems logical that if there are two known values given for the interior angles of a triangle, the third value could be found using this...

Given an isosceles triangle, and the value of one angle, find the missing values. There are some special properties about isosceles triangles. Use the triangle sum theorem to solve this problem. Watch this video to see how the instructor...

What makes a figure a polygon? Does it have three or more sides? Is it a closed figure? If the answer is yes to both of those questions then it's a polygon. But wait! Some of these polygons have special names based on the number of sides...

Squares, pentagons, triangles, polygons. How is it possible to figure out the sum of the interior angles of any of these multi-faceted shapes? There's got to be a formula. Of course there's a formula. That's what algebra is all about,...

Two figures are congruent if they have the same size and shape. Line segments can also be congruent if they are of the same length. Vertical angles created by intersecting lines are always congruent. Polygons that have matching angles...

One base, triangular sides, and defined polygons are all parts of what make up a pyramid. Check out this video and see the instructor draw pictures of a variety of pyramids. She identifies the specific parts and gives them names based on...

Finding the missing values of two angles in an isosceles triangle is not as difficult as it sounds. But how can two out of three angle's measurements be found? Well, there are special properties about an isosceles triangle which make...

The interior angles of any and ALL triangles adds up to 180 degrees. So if given two of the angle degrees, is it possible to find the value of the third angle? Yes! Use the triangle sum theorem to solve for the missing angle. Watch this...

What's a trigonometric ratio? It is a ratio between two sides of a right triangle. In this problem, find sin(A) in the given right triangle. Use the ratio of the opposite side divided by the hypotenuse to find sin(A). The instructor...

A right triangle. Two given measurements for two side lengths and one unknown length. Use the Pythagorean theorem to solve this problem and find the missing value. Squares and square roots are used in this problem and don't worry when...

This video shows you and your class how to make an origami hat. Why would you do such a thing? If you think about it origami builds eye hand coordination, is fun, is culturally significant, and this hat, is full of measurable angles....

Does watching a person do a math problem help you understand a mathematical concept? If it does then this clip will be a great help. The tutor in this clip completes a geometry problem involving tangents, circles, and the Pythagorean...

Is it possible to take an equilateral triangle and cut it in half to make a 30-60-90 special triangle to make it easier to solve a problem? Why yes, of course! It's even possible to find the missing length without using the Pythagorean...

One given angle and one given length equals an unknown height. What? Here's a word problem that can be solved given two pieces of information by using the correct formula. Watch the instructor explain how to use the tangent ratio formula...

Use this video to help teach the Pythagorean Theorem. The video can be downloaded, there is a transcript of the video, and a teacher's guide to aid in using the video. [21:38]

An MIT engineering professor leads teachers and students through an activity in triangle formation and probability that requires a meter stick and other basic classroom materials. This video [33:08] is accompanied by a teacher's guide,...