Acertain rock rises almost straight upward from the valley floor. from one point, the angle of elevation of the top of the rock is 22.6 degrees. from a point 191 m closer to the rock, the angle of elevation of the top of the rock is 39.9 degrees. how high is the rock?

Seeing the image attached, we can then get tan (22.6) = opposite/adjacent = opposite/191, and tan(22.6)*191=opposite side length, which is the hypotenuse of the right triangle. sin (39.9) is then opposite/hypotenuse, and we want to find the opposite (the height). To get that, we have
sin(39.9)=opposite/tan(22.6)*191 and then sin(39.9)*tan(22.6)*191=height

What mathematical statement is missing ? ? the answer is b