1. The problem is to understand the trigonometric relationship involving sine of an angle $\theta$ in a right triangle. 2. The sine of an angle $\theta$ is defined as the ratio of the length of the side opposite the angle to the length of the hypotenuse: $$\sin(\theta) = \frac{\text{opposite}}{\text{hypotenuse}}$$ 3. If you want to find the hypotenuse $h$ given the opposite side and the angle $\theta$, you rearrange the formula: $$\sin(\theta) = \frac{\text{opposite}}{h} \implies h = \frac{\text{opposite}}{\sin(\theta)}$$ 4. This means the hypotenuse is equal to the length of the opposite side divided by the sine of the angle. 5. So, the expression $h = \frac{\text{opposite}}{\sin(\theta)}$ is just the rearranged formula to solve for the hypotenuse when you know the opposite side and the angle $\theta$. This explains the notation and the relationship clearly.