Question

what equation can be used to solve for x? tan(40°)=19/x sin(40°)= x/40 cos(40°)=x/19 sin(40°)=x/19

Explanation:

Step1: Recall trigonometric - ratio definitions

In a right - triangle, $\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}$. Here, the angle $\theta = 40^{\circ}$, the adjacent side to the $40^{\circ}$ angle is $x$ and the hypotenuse is 19.

Step2: Write the cosine equation

Based on the cosine ratio, $\cos(40^{\circ})=\frac{x}{19}$.

Answer:

Cos(40°)=x/19