Given two sides of a right triangle, to find a missing angle, follow the steps below.
Step 01: Find an adequate trigonometric identity.
Since the two legs of the triangle are known, use the equation for a tangent:
Step 02: Substitute the values in the equation.
In this exercise,
8 is the opposite side;
5 is the adjacent side to θ.
Then,
Step 03: Find θ.
Use tan⁻¹ to find θ.
Answer: θ = 57.99°.