Geometry - Sin & Cos

In order to find the measure of an interior angle using Sine, Cosine, and Tangent, you must use the inverse (sin ^-1 cos ^-1 tan ^-1) For this problem you have to use Tan ^-1 because the measurements they give you are the opposite and adjacent sides in relation to the angle they give you. What your equation should look like at first is this: tanX=11/9.1. You then isolate X and simplify. Your problem should look like this: X=tan ^-1(1.2) Then you plug this into your calculater. Hope I was helpful

8m*18m