Answer:
15.28
Explanation:
To start, I found the height of the triangle 50 degrees.
This would be tan 50° = x/40
Multiply 40 to the other side to get 40 tan 50° = 47.67
Since you're looking for the height from the roof to the mast, do the same thing with the 39° triangle, getting tan 39° = x/40
Mult. 40 over to get 40 tan 39° = 32.39
47.67 - 32.39 = 15.28
15.28 is the height from the roof to the mast