If we were to use trig to solve for the missing angle of a right triangle, we would be using tangent because from angle A, we are solving for side a by using side b. Tan = opposite/adjacent. The opposite side is a and the adjacent side is b=120ft. So, now we solve this equation: Tan(20 degrees)= a/120ft. The goal is to isolate a, so we must multiply both sides by 120, but not before finding the tangent of 20 degrees. The tangent of 20 degrees is 0.36397023426, and if we multiply that by 120, we get 43.6764281119. You can either round this or write it in a different way, depending on what you are learning right now. The other way to write this would be a = 120 tan 20 degrees. Hope this helped!
