Instructional Video4:35
Curated Video

Classifying Triangles using the Pythagorean Theorem

K - 5th
Learn about the characteristics of right, acute, and obtuse triangles. This video demonstrates how to determine if a triangle is right using the theorem and highlights common mistakes students make.
Instructional Video11:32
Curated Video

Converse of the Pythagorean Theorem and Triangle Inequality Theorem

9th - 12th
In this video, the teacher explains how to use the triangle inequality theorem to determine if three side measurements can form a triangle. They also teach how to use the converse of the Pythagorean theorem to determine if a triangle is...
Instructional Video15:20
Brian McLogan

How to Solve the ambiguous case

12th - Higher Ed
👉 Learn how to determine if a given SSA triangle has 1, 2 or no possible triangles. Given two adjacent side lengths and an angle opposite one of them (SSA or ASS), then there are 3 possible cases: there can be 1 solution, 2 solutions,...
Instructional Video1:55
NUMBEROCK

Triangles

K - 5th
Skateboards, mountain climbing, billiards' Don't you just love this stuff? That's why NUMBEROCK put it all into this song about triangles that is filled with real-world connections. Triangles are all around us, so it is easy to make this...
Instructional Video3:36
Curated Video

Classifying Triangles Based On Angle Properties

3rd - 5th
Classifying triangles based on angle properties.
Instructional Video4:24
Curated OER

What are Acute, Obtuse, and Right Triangles?

5th - 8th
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...
Instructional Video
Virtual Nerd

Virtual Nerd: How Do You Classify Triangles?

9th - 10th Standards
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]
Instructional Video
CK-12 Foundation

Ck 12: Elem Math: Overview of Special Triangles

3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on how to find missing angles in triangles.
Instructional Video
CK-12 Foundation

Ck 12: Elem Math: Overview of Triangle Classifications

3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on how to classify triangles.
Instructional Video
Sophia Learning

Sophia: Classifying Triangles

6th - 8th
In this video tutorial, students learn how to classify triangles based on the angles. Topics include right, obtuse, and acute triangles. A short assessment is included to follow the lesson. [4:40]
Instructional Video
Art of Problem Solving

Art of Problem Solving: Area of an Acute Triangle

9th - 10th Standards
Video tutorial uses examples to reinforce understanding of how to find the area of an acute triangle. [8:21]
Instructional Video
Sophia Learning

Sophia: Triangle Height: Lesson 3

9th - 10th
This lesson will demonstrate how to locate the height in an obtuse, right, and acute triangle. It is 3 of 5 in the series titled "Triangle Height."