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Online Pythagorean Theorem Calculator

Online Pythagorean Theorem Calculator

Easily calculate any side of a right triangle using the Pythagorean theorem with this precise and user-friendly online calculator. Ideal for students, engineers, architects, and more.

RESULT

a = 3
A = 6

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What Is This Tool?

This calculator applies the Pythagorean theorem to find the length of one side of a right triangle when the lengths of the other two sides are known. It supports calculations for the legs and hypotenuse based on the formula a² + b² = c².

How to Use This Tool?

  • Enter the lengths of any two known sides of the right triangle: a, b, or c
  • Leave the side you want to calculate empty or set to zero
  • Click the calculate button to compute the missing side length
  • Review the displayed result to use in your geometry or design work

Key Features

  • Calculates any side of a right triangle given the other two sides
  • Uses the Pythagorean theorem formula and its rearranged forms
  • Supports variables: leg a, leg b, and hypotenuse c
  • Provides high-precision results with accurate square-root calculations
  • Browser-based and easy to use without requiring downloads

Examples

  • For a right triangle with legs a = 9 and b = 12, the hypotenuse c is calculated as c = √(9² + 12²) = 15
  • Given hypotenuse c = 13 and leg b = 5, calculate leg a as a = √(13² - 5²) = √(169 - 25) = √144 = 12
  • If hypotenuse c = 10 and leg a = 6, find leg b using b = √(10² - 6²) = √(100 - 36) = √64 = 8

Common Use Cases

  • Solving right triangle side lengths in geometric problems
  • Assisting in trigonometry studies and physics calculations
  • Supporting construction measurements and architectural design
  • Navigating and surveying distances involving right angles
  • Designing objects and structures requiring precise side calculations

Tips & Best Practices

  • Ensure that you input correct side lengths according to the right triangle properties
  • Remember the hypotenuse (c) is always the longest side
  • Use consistent measurement units for all sides entered
  • Double-check inputs to avoid invalid entries that produce no real solutions
  • Use the calculator for quick verification but cross-check complex problems manually when needed

Limitations

  • Applicable only to right triangles with one 90-degree angle
  • Does not compute real results if the hypotenuse is smaller than either leg
  • Cannot solve triangles if insufficient side length information is provided
  • Invalid inputs that violate triangle inequality rules will not yield valid outputs

Frequently Asked Questions

What is the Pythagorean theorem used for in this calculator?
The Pythagorean theorem relates the sides of a right triangle using the formula a² + b² = c² to calculate an unknown side length.

Can I use this calculator for triangles that aren’t right angled?
No, this tool works only for right triangles; it requires one 90-degree angle to apply the theorem correctly.

What should I do if my inputs don’t produce a valid result?
Check that the hypotenuse is the longest side and that the entered values obey triangle rules. Invalid inputs can produce no real numeric solution.

Key Terminology

Leg
One of the two sides that form the right angle in a right triangle, labeled as a or b.
Hypotenuse
The side opposite the right angle in a right triangle, labeled as c, and is the longest side.
Pythagorean theorem
A fundamental relation in geometry defined as a² + b² = c² connecting the sides of a right triangle.

Quick Knowledge Check

Which side is the hypotenuse in a right triangle?