Question

Find the measure of the indicated missing angle. Round your answer to the nearest tenth. A. 67.4. B. 55.2. C. 34.8. D. 22.6. The numbers are 13, 12, and 5.

Answer 1

Since 5^2 + 12^2 = 13^2, this is a right triangle with hypotenuse 13. The angle opposite the side 5 satisfies

sin θ = 5/13 ⇒ θ = arcsin(5/13) ≈ 22.6°.

So the correct choice is D (22.6°).