The equation tan−1 (8.9/7.7) = x can be used to find the measure of angle LKJ.What is the measure of angle LKJ? Round to the nearest whole degree.

tan−1 (8.9/7.7) = x can also be written as x = arctan (1.156).

Using my TI-83 calculator's inverse tangent function key, I get x = 0.858 radian.  This is equivalent to 49.135 degrees, which we must round off to the nearest whole degree:  49 degrees.