Question

solve for x. set up the function, using cosine. cos(?) = / cosine value submit

Explanation:

Step1: Recall cosine formula

In a right - triangle, $\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}$.

Step2: Identify angle, adjacent and hypotenuse

The given angle $\theta = 20^{\circ}$, the adjacent side to the $20^{\circ}$ angle is $4$, and the hypotenuse is $x$.
So, $\cos(20^{\circ})=\frac{4}{x}$.

Answer:

$\cos(20^{\circ})=\frac{4}{x}$