Question

A flag post 10m long is fixed on top of a tower. From a point on horizontal ground, the angle of elevation of the top and bottom of the flag post are 40° and 33° respectively. Calculate height of the tower??​

Answer 1

Answer:

Let AB is the tower of height x m and BC is the flagstaff of height 10 m. Let D be the point from where the angles of elevation are 450 and

600 such that BDA = 450 and CDA = 600

In DAB, tan 450 = AB/AD

1 = x/AD AD = x

In DAC, tan 600 = AC/AD

3

= (10+x)/x

3

x = 10+x

(

3

-1)x = 10

x = 10/(

3

- 1) = 10/(

3

- 1) x (

3

+ 1)/(

3

+ 1)

x = 5(

3

+ 1)