The angles of depression of the top and bottom of a building 50 meters high as observed from the top of a tower are 30 and 60 respectively. Find the height of the tower, and also the horizontal distance between the building and the tower.
Answers
In ΔBTP,
tan 30° = TP/BP
1/√3 = TP/BP
BP = TP√3
In ΔGTR,
tan 60° = TR/GR
√3 = TR/GR
GR = TR/√3
As BP = GR
TP√3 = TR/√3
3 TP = TP + PR
2 TP = BG
TP = 50/2 m = 25 m
Now, TR = TP + PR
TR = (25 + 50) m
Height of tower = TR = 75 m
Distance between building and tower = GR = TR/√3
GR = 75/√3 m = 25√3 m
The angles of depression of the top and bottom of a building 50 meters high as observed from the top of a tower are 30 and 60 respectively. Find the height of the tower, and also the horizontal distance between the building and
the tower.
Let AB be the building = 50
CE be the tower = 50+y
Let BC = AD = x=the distance between them
tan 30º =DE/AD
1/V3 = y/x
In right AEBC,
tan60º = CE /BC
V3 = (50 + y)/ X
V3x = 50 + y
V3(V3y) = 50 + y..from (i)
3y - y = 50
2y = 50
y = 25
Height of the tower CE = 50 + y
= 50 + 25
= 75 cm
Now taking the value of y in (i), we get
x = 3 x 25
x = 1.73 x 25
x = 43.25
Required horizontal distance x = 43.25 m