Question

Which equation can be used to find the measure of angle LKJ?

cos−1(StartFraction 8.9 Over 10.9 EndFraction) = x
cos−1(StartFraction 10.9 Over 8.9 EndFraction) = x
sin−1(StartFraction 10.9 Over 8.9 EndFraction) = x
sin−1(StartFraction 8.9 Over 10.9 EndFraction) = x

Answer 1

cos⁻¹(8.9 / 10.9) = x

Reason: cos(angle) = adjacent/hypotenuse. For ∠LKJ the side of length 8.9 is adjacent and 10.9 is the hypotenuse, so x = arccos(8.9/10.9).