#### Answer

sine

#### Work Step by Step

The sine ratio is given as:
sin θ = $\frac{opposite}{hypotenuse}$
The cosine ratio is given as:
cos θ = $\frac{adjacent}{hypotenuse}$
Therefore, the sine ratio is the one that relates the length of the side opposite to an acute angle in a right triangle to the length of the hypotenuse of the triangle.