# Hypotenuse, opposite, and adjacent

CCSS Math: HSG.SRT.C.6, HSG.SRT.C.8

In a right triangle, the hypotenuse is the longest side, an "opposite" side is the one across from a given angle, and an "adjacent" side is next to a given angle.

We use special words to describe the sides of right triangles.

The

**hypotenuse**of a right triangle is always the side opposite the right angle. It is the longest side in a right triangle.The other two sides are called the opposite and adjacent sides. These sides are labeled in relation to an angle.

The

**opposite side**is across from a given angle.The

**adjacent side**is the non-hypotenuse side that is next to a given angle.Putting it all together from the perspective of $\angle A$:

And from $\angle B$:

## Practice

## Why are these words important?

We're about to learn the trigonometric functions—sine, cosine, and tangent—which are defined using the words hypotenuse, opposite, and adjacent.