Flipped Math
Unit 6 Review: Similar Figures
After a short review of the material from the Similar Figures Unit, pupils work through 18 problems to further practice the skills from the unit. Scholars apply those skills in the application problems at the end of the review.
Flipped Math
Side Splitter Theorem
Apply perspective to similarity. Individuals learn about the Side Splitter Theorem by looking at perspective drawings. Pupils use the theorem and its corollary to find missing lengths in figures. Next, they practice using the theorem and...
CK-12 Foundation
Triangle Proportionality: Lesson
Look at proportionality from a parallel perspective. A section of an expansive geometry playlist introduces the Triangle Proportionality Theorem. Using the theorem, the video shows how to determine missing measurements in triangles.
Mathematics Assessment Project
Modeling Motion: Rolling Cups
Connect the size of a rolling cup to the size of circle it makes. Pupils view videos of cups of different sizes rolling in a circle. Using the videos and additional data, they attempt to determine a relationship between cup...
Brightstorm
Pythagorean Theorem Proofs
Your class knows the Pythagorean Theorem, but can they prove it? A series of three videos shows two proofs of the Pythagorean Theorem and use it to classify triangles.
TED-Ed
Why Are Manhole Covers Round?
Discover the peculiar geometric property of the curve of constant width, the Reuleaux triangle, and their intriguing connection to manhole covers with yet another fascinating TED-Ed video.
Khan Academy
Khan Academy: Geometry: Challenging Similarity Problem
Explains how to determine unknown side lengths in a complex diagram that involves similar triangles. [9:53]
Khan Academy
Khan Academy: Geometry: Triangle Area Proofs
Proof that the area of any triangle is half the product of the base and the height. Three different types of triangles are used to prove the formula. [10:23]
Khan Academy
Khan Academy: Geometry: Ca Geometry: More on Congruent and Similar Triangles
Demonstrates solutions to problems #17-20 of California Geometry released state test questions. Problems address understanding of similar triangles, parallelograms and properties of the diagonals of parallelograms. [11:11]
Math Planet
Math Planet: Geometry: Triangles
Discussion of triangles through the use of examples and a video lesson. [1:08]
Virtual Nerd
Virtual Nerd: What Is a Triangle?
This tutorial explains triangles and their different types. [5:58]
Virtual Nerd
Virtual Nerd: How Do You Classify Triangles?
If you know what kind of triangle you're looking at, it's much easier to figure out how to solve for various sides and angles. Use this tutorial to practice classifying triangles. [7:15]
Virtual Nerd
Virtual Nerd: What Are Acute, Obtuse, and Right Triangles?
Take a look at this tutorial and learn about some of the different kinds of triangles. [4:25]
Virtual Nerd
Virtual Nerd: What Are Equilateral, Isosceles, and Scalene Triangles?
Watch this tutorial to learn about some of the different kinds of triangles. [5:33]
Khan Academy
Khan Academy: Triangles: Triangle Angle Example 3
Explains how to solve for multiple missing angles in a diagram composed of multiple triangles using the triangle sum theorem and other angle relationships.
Khan Academy
Khan Academy: Triangles: Triangle Area Proofs
A video proving that the area of any triangle is half the product of the base and the height.
Khan Academy
Khan Academy: Triangles: Similarity Example Problems
Explains how to identify and use similar triangles in order to determine unknown side lengths in two given diagrams.
Virtual Nerd
Virtual Nerd: Find Missing Angles in an Isosceles Triangle Using Right Triangles
Discover how identifying your triangle first can be very helpful in solving for a missing interior angle measurement. [3:40]
Khan Academy
Khan Academy: Geometry: Part 1 of Proof of Heron's Formula
Demonstrates how to derive a version of Heron's formula using the Pythagorean Theorem and the formula for the area of a triangle. Applies Heron's formula to solve a sample problem. [10:59]
Khan Academy
Khan Academy: Example Involving an Isosceles Triangle and Parallel Lines
This video demonstrates how to use the triangle sum theorem, properties of isosceles triangles, and special angle pairs formed when parallel lines are cut by a transversal to set up an equation using given algebraic expressions for angle...
Khan Academy
Khan Academy: Triangles: Pythagorean Theorem Ii
More Pythagorean Theorem examples. Introduction to 45-45-90 triangles.
Khan Academy
Khan Academy: Basic Triangle Proofs Module Example 2
A video proving that the given triangles are congruent by ASA.
Khan Academy
Khan Academy: Proof of Heron's Formula (2 of 2)
Sal proves Heron's Formula for finding the area of a triangle solely from its side lengths.