Question

solve for the missing angle.

Explanation:

Step1: Use cosine - inverse formula

Let the missing angle be $\theta$. We know that $\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}$. Here, adjacent side = 13 and hypotenuse = 18. So, $\theta=\cos^{- 1}(\frac{13}{18})$.

Step2: Calculate the angle

Using a calculator, $\cos^{-1}(\frac{13}{18})\approx43.3^{\circ}\approx44^{\circ}$

Answer:

$44^{\circ}$