Pythagorean theorem

Math

Definition

In a right triangle, the square of the hypotenuse (the side opposite the right angle) equals the sum of the squares of the other two sides. This theorem is used to find a missing side length in any right triangle.

Examples

  • A right triangle with legs 3 and 4 has hypotenuse √(9 + 16) = 5
  • Finding the distance between two points on a coordinate plane using the distance formula, which is derived from the Pythagorean theorem
Key Fact

a² + b² = c², where c is the hypotenuse

Related Terms

Special right triangles Solving right triangles Soh-cah-toa Triangles

Study This Concept

Practice Pythagorean theorem with free review games in these units:

Geometry Unit 8: Right Triangles and Trigonometry