Question

which trig function would you use to solve for x? 20 55° x sine tangent cosine secant

Explanation:

Step1: Recall trigonometric ratios

In a right - triangle, \(\sin\theta=\frac{\text{opposite}}{\text{hypotenuse}}\), \(\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}\), \(\tan\theta=\frac{\text{opposite}}{\text{adjacent}}\), \(\sec\theta=\frac{\text{hypotenuse}}{\text{adjacent}}\).
Here, the hypotenuse is \(20\), the adjacent side to the \(55^{\circ}\) angle is \(x\).

Step2: Match the ratio

Since we have the hypotenuse and the adjacent side, \(\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}\). So \(\cos(55^{\circ})=\frac{x}{20}\).

Answer:

cosine