A triangle is a three-sided polygon. The sum of its interior angles always equals 180°. Triangles are everywhere—from road signs to pyramids—making them super important in math and the real world.
Triangles can be classified by their side lengths or angle sizes:
By Sides:
By Angles:
Understanding triangles is the foundation of trigonometry. Once you master triangles, you’ll find it easier to understand how their angles and sides relate using trigonometric functions.
From designing buildings to solving mysteries in navigation, triangles play a vital role!
A traffic sign in the shape of an equilateral triangle.
A ladder leaning against a wall forms a right triangle.
Triangles are three-sided shapes, and learning their types is the first step in understanding trigonometry.