Math Dictionary / Hypotenuse

Hypotenuse

The hypotenuse is the longest side of a right triangle.

GeometryGrade 8Algebra 1GEDSATACT

What it means

It is always across from the right angle.

Also called: longest side of a right triangle

Examples

In a 3-4-5 right triangle, 5 is the hypotenuse
The hypotenuse is labeled c in a^2 + b^2 = c^2
It is across from the 90-degree angle

Common mistake

The hypotenuse exists only in a right triangle.

Try one

Question: A right triangle has side lengths 5, 12, and 13. Which side is the hypotenuse?

Show answer

13, because it is the longest side.

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