Triangle Types

Free interactive math game: Triangle Types — Acute, Right, Obtuse. Part of the Geometry (Angles) category on MathKite.

Example problems

Taken from the generator that powers this exercise. A fresh set appears every time the page is opened, and the printable worksheet holds ten of them.

  1. Angles of the triangle: 90°, 52°, 38° What type of triangle is this?
  2. Angles of the triangle: 90°, 42°, 48° What type of triangle is this?
  3. Angles of the triangle: 109°, 53°, 18° What type of triangle is this?
  4. Angles of the triangle: 90°, 34°, 56° What type of triangle is this?

About this exercise

Classifying a triangle by its angles.

How to solve it

All angles under 90 makes it acute, one angle of exactly 90 makes it right, and one angle over 90 makes it obtuse.

Worked example

Angles of 30, 60 and 90 make a right triangle.

Common mistake

Expecting two large angles. A triangle can hold at most one angle of 90 degrees or more.