Trig triangle word problem

Dec 2009
103
0
From a point on level ground, the angle of elevation to the top of a vertical building is a. From the point d feet further away from the building on level ground and in line with the building and the first point, the angle of elevation of to the top of the building is B. Express the height of the building in terms of a, b and d.
help! I'm not sure how to draw the angles of elevation.
 
May 2010
1,260
410
Mauritius
Maybe this sketch will help you: