Definition

Hypotenuse and Legs of a Right Triangle

A right triangle contains one 90°90° angle, typically marked with a small square in the corner. Its three sides have specific names based on their position relative to the right angle:

  • The hypotenuse is the side directly opposite the 90°90° angle. It is always the longest side of a right triangle.
  • The other two sides are called legs. Each leg forms one side of the right angle.

These labels apply regardless of how the triangle is oriented — the hypotenuse is always identified as the side across from the right angle.

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Updated 2026-05-02

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