Reverse Hypotenuse Calculator

Enter the hypotenuse and the length of the known side into the Reverse Hypotenuse Calculator. The calculator will evaluate and display the length of the missing side.

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Reverse Hypotenuse Formula

Use this calculator when you know the hypotenuse and one side of a right triangle and need the other side. Keep both inputs in the same unit so the result is returned in that same unit.

H^2 = S_1^2 + S_2^2

S_2 = \sqrt{H^2 - S_1^2}

Variable Guide

How to Calculate the Missing Side

1. Square the hypotenuse.
2. Square the known side.
3. Subtract the known-side square from the hypotenuse square.
4. Take the square root of the result.

Examples

S_2 = \sqrt{50^2 - 20^2} = 45.826

S_2 = \sqrt{30^2 - 10^2} = 28.284

Input Rules

• The hypotenuse must be longer than the known side.
• This calculation applies only to right triangles.
• If both values are equal, the result is zero, which is a degenerate case rather than a true triangle.
• If the value inside the square root would be negative, the inputs are not valid for a right triangle.

Quick Reference

Common Uses