Question

Triangle A B C is shown. Angle A C B is a right angle. The length of hypotenuse A B is 13, the length of C B is 12, and the length of A C is 5. Angle C A B is x.
Which equation can be used to find the measure of angle BAC?

tan−1(StartFraction 5 Over 12 EndFraction) = x
tan−1(StartFraction 12 Over 5 EndFraction) = x
cos−1(StartFraction 12 Over 13 EndFraction) = x
cos−1(StartFraction 13 Over 12 EndFraction) = x

Answer 1

tan⁻¹(12/5) = x

Reason: For angle A, the opposite side is CB = 12 and the adjacent side is AC = 5, so tan(A) = 12/5, hence A = tan⁻¹(12/5).