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
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 Obtuse Triangle

9th - 10th Standards
Video tutorial uses examples to reinforce understanding of how to find the area of an obtuse triangle. [6:44]
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."