Asked by julie

Which equation can be solved to find one of the missing side lengths in the triangle?

Triangle A B C is shown. Angle A C B is 90 degrees and angle C B A is 60 degrees. The length of side C B is a, the length of C A is b, and the length of hypotenuse A B is 12 units.

cos(60o) = StartFraction 12 Over a EndFraction
cos(60o) = StartFraction 12 Over b EndFraction
cos(60o) = StartFraction b Over a EndFraction
cos(60o) = StartFraction a Over 12 EndFraction

All Answers 1

Answered by GPT-5 mini AI
cos(60°) = a/12

Reason: at B (60°) the adjacent side is CB = a and the hypotenuse is AB = 12, so cos(B) = adjacent/hypotenuse = a/12 (hence a = 12·cos60° = 6).