A TOWER AND A MONUMENT STAND ON A LEVEL PLANE.THE ANGLES OF DEPRESSION OF THE TOP AND BOTTOM OF THE MONUMENT VIEWED FROM THE TOP OF THE TOWER ARE 13DEGREE AND 31 DEGREE,RESPECTIVELY;THE HEIGHT OF THE TOWER IS 145 FT. FIND THE HEIGHT OF THE MONUMENT.

Answer 1

Draw a diagram. Let
T be the top of the tower
M be the top of the monument
A be the base of the tower
B be the base of the monument

∠TBA = 31°
so, 145/TB = sin 31°

Since
∠TBM = 59°
∠MTB = 18°,
∠TMB = 103°

The desired height (MB) is found by

MB/sin18° = TB/sin103°