# Classify Triangles

A triangle is a steel percussion instrument in the shape of an equilateral triangle. Different-sized triangles produce different musical notes when struck with a metal rod.

A triangle (**△**) is a polygon with three sides. The triangle can be classified in two ways: by their angle measures or by their side length.

Learn more about classifying triangles by reading the explanation below.

**Practice:** Answer the following exercises about classifying triangles.