GeometryBeginner9 min read • October 4, 2025

Pythagorean Theorem: Geometry\'s Foundation

Right triangles unlock a lot of the world. This formula tells you why.

The Formula

a² + b² = c²

Quick Example

If a = 6 and b = 8, then c = √(36 + 64) = √100 = 10.

How to Remember

  • Think “legs squared add up to hypotenuse squared”
  • Draw a right triangle and label the sides each time
  • Keep units consistent—always

Try This

Measure the diagonal of your laptop screen with the theorem. Does it match the advertised inches?

Related: Distance Formula →