Khan Academy: Classifying Triangles

Learn to categorize triangles as scalene, isosceles, equilateral, acute, right, or obtuse.

Explains how to classify a triangle just by knowing the angle sizes. [5:30]

You say you can't categorize a triangle because you don't know the length of the sides. Guess what? If you know the size of the angles you can!

In this exercise, students practice recognizing triangle types. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

In this exercise, students practice classifying shapes by line and angle types. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

Classify shapes based on pictures or attributes, such as angle types and side-lengths. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Lindsay classifies a shape based on hints about its sides and angles.

Practice identifying triangles by their angles as acute, right, or obtuse. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Practice identifying triangles by their side-lengths as equilateral, isosceles, or scalene. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Sal categorizes shapes based on their sides and angles.