8th Grade · Geometry
Pythagorean Theorem
8.G.B.6
Definition
In a right triangle, the sum of the squares of the two legs equals the square of the hypotenuse. a squared plus b squared equals c squared.
Examples
- 3² + 4² = 9 + 16 = 25 = 5², so c = 5.
- Works ONLY for right triangles.
Key rule
c is always the hypotenuse — the longest side, across from the right angle.
Memory hook
a² + b² = c², for right triangles only.