What is the Pythagorean Theorem?
April 12, 2026 • 9 min read • Math
The Pythagorean theorem states that in a right triangle, the square of the hypotenuse equals the sum of squares of the other two sides: a² + b² = c².
a² + b² = c²
Understanding the Parts
c = Hypotenuse (longest side, opposite right angle)
a and b = Legs (the two shorter sides)
Example Problem
Find the hypotenuse of a right triangle with legs of 3 and 4.
c² = 3² + 4² = 9 + 16 = 25
c = √25 = 5
Finding a Leg
If c = 13 and a = 5, find b:
b² = c² - a² = 169 - 25 = 144
b = √144 = 12
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