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Pythagorean Theorem Calculator

Find missing sides of right triangles using a² + b² = c². Perfect for students learning geometry with step-by-step solutions.

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Enter Known Values

Pythagorean Theorem
a² + b² = c²
Right Triangle Visualization
side a side b hypotenuse c
One of the sides forming the right angle
The other side forming the right angle
The longest side opposite the right angle
💡 Tip: Enter any two known values, and we'll calculate the third side for you.

Solution

Step-by-Step Solution

Enter two known values to see the step-by-step solution

Understanding the Pythagorean Theorem

What is the Pythagorean Theorem?

The Pythagorean Theorem is one of the most famous mathematical formulas, discovered by the ancient Greek mathematician Pythagoras around 500 BCE. It states that in a right triangle, the square of the hypotenuse (the longest side) equals the sum of squares of the other two sides.

a² + b² = c²
Where c is the hypotenuse, and a and b are the other two sides

Key Components

  • Right Triangle: Must have one 90° angle
  • Legs (a, b): The two sides that form the right angle
  • Hypotenuse (c): The longest side, opposite the right angle

Common Applications

  • Construction: Ensuring buildings and structures are square
  • Navigation: Calculating shortest distances and routes
  • Engineering: Designing ramps, roofs, and support structures
  • Physics: Vector calculations and force analysis

How to Use It

Find Hypotenuse: c = √(a² + b²)
Find a Side: a = √(c² - b²)
Check Right Angle: Does a² + b² = c²?

Famous Example: 3-4-5 Triangle

3² + 4² = 5²
9 + 16 = 25 ✓
This is the most famous Pythagorean triple, used by builders and craftsmen for centuries.

Other Pythagorean Triples

5, 12, 13
5² + 12² = 13² (25 + 144 = 169)
8, 15, 17
8² + 15² = 17² (64 + 225 = 289)
7, 24, 25
7² + 24² = 25² (49 + 576 = 625)

Historical Context

While named after Pythagoras, this theorem was known to many ancient civilizations, including the Babylonians, Egyptians, and Indians, centuries before Pythagoras. The Egyptians used the 3-4-5 triangle to create right angles when building pyramids.

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