Question

fall 2025 geometry b wwva solving for side lengths of right triangles cos(60°)=a/12 cos(60°)=b/a cos(60°)=a/b

Explanation:

Step1: Recall cosine definition

In a right - triangle, $\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}$. If the angle $\theta = 60^{\circ}$, and assuming the hypotenuse is $12$ and the side adjacent to the $60^{\circ}$ angle is $a$. Then $\cos(60^{\circ})=\frac{a}{12}$.

Step2: Use cosine value

We know that $\cos(60^{\circ})=\frac{1}{2}$. So the equation $\cos(60^{\circ})=\frac{a}{12}$ can be used to find the side - length $a$.

Answer:

$\cos(60^{\circ})=\frac{a}{12}$