From the top of a pole house A in a street, the angles of elevation and depression of the top and foot of house B on the opposite side of the street are 60° and 30°, respectively. If the height of pole house A is 21m, then what is the height (in m) of house B? (Correct to one decimal place)

From the top of a pole house A in a street, the angles of elevation an

1.	From the top of a pole house A in a street, the angles of elevation and depression of the top and foot of house B on the opposite side of the street are 60° and 30°, respectively. If the height of pole house A is 21m, then what is the height (in m) of house B? (Correct to one decimal place)
A.	57
B.	67
C.	84
D.	80
Answer» D. 80