Question

Triangle G E F is shown. Angle G E F is a right angle. The length of hypotenuse F G is 14.5 and the length of F E is 11.9. Angle B F E is theta.
Which equation can be used to find the measure of angle GFE?

cos−1(StartFraction 14.5 Over 11.9 EndFraction) = θ
cos−1(StartFraction 11.9 Over 14.5 EndFraction) = θ
sin−1(StartFraction 11.9 Over 14.5 EndFraction) = θ
sin−1(StartFraction 14.5 Over 11.9 EndFraction) = θ

Answer 1

cos−1(11.9/14.5) = θ

Reason: For ∠GFE the adjacent side is FE = 11.9 and the hypotenuse is FG = 14.5, so cos θ = adjacent/hypotenuse = 11.9/14.5, hence θ = arccos(11.9/14.5).