Question

a 7 m long flagstaff is fixed on the top of a tower standing on tha horizontal plane. from point on the ground the angles of elevation of the top and bottom of the Flagstaff are 60° and 45° respectively. find the height of the tower correct to one place of decimal

Answer 1

Let's take height of tower is h and Base is b...

Tan45 = h/b
b = h -------eq 1

Tan60 = (h+7)/b

root3× b = h+7
Now put value of b from eq 1

root3×h -h = 7
h (root3-1) = 7
h=7/(root3-1)
Put root3 = 1.7
h=7/(1.7-1)
h=7/0.7
h=70/7
h = 10m

Thanks