Right triangle

What is a Right Triangle?

A right triangle is a special shape with three sides and three corners. Two of its sides meet at a right angle, which is exactly 90 degrees. Imagine the corner of a book or a window—that is a right angle! The side across from this right angle is called the hypotenuse, and it is always the longest side of the triangle.

Right triangles are very useful. They help us solve many problems in math and everyday life. For example, they can help us measure heights of tall objects without climbing them!

Fun Facts About Right Triangles

Right triangles can be thought of as half of a rectangle split along its diagonal. When the rectangle is a perfect square, the right triangle has two sides that are the same length.

One of the most famous rules in math is the Pythagorean theorem. It tells us that if we know the lengths of the two shorter sides, called legs, we can find the length of the hypotenuse by using the formula a² + b² = c².

Right triangles also help us understand angles better. They are the basis of trigonometry, which shows how angles and side lengths are related in many real-world situations.

A Picture of a Right Triangle

This picture shows a right triangle with its right angle at C, hypotenuse c, and legs a and b.