Posted by john on .
From a point A is 8.20 meters above level ground,the angle of elevation of the top of a building is 31degrees 20 min and the angle of depression of the base of the building is 12degree 50 min. Approximate the heighth of the building

Pre cal 
Steve,
If the distance of A is d, and the building's height is h,
(h8.2)/d = tan 31°20'
8.2/d = tan 12°50'
so, equating d,
(h8.2)/tan 31°20' = 8.2/tan 12°50'
(h8.2)/.6088 = 8.2/.2278
h = 30.11 m