Consider a right triangle where one angle is $30^{ ext{o}}$ and the length of the side opposite this angle is 5 units. What is the length of the hypotenuse of the triangle?
Use the sine function, which is defined as the ratio of the length of the opposite side to the length of the hypotenuse:
$$\sin(\theta) = \f\frac{\text{opposite}}{\text{hypotenuse}}$$
In this case, the angle $\theta$ is $30^{\text{o}}$.