Question

13. A ladder 9 m long reaches a point 9 m
below the top of a vertical flagstaff.
From the foot of the ladder, the eleva-
tion of the flagstaff is 60°. What is the
height of the flagstaff?​

Answer 1

Step-by-step explanation:

CD=AD=9m

∵△ACD is isosceles.

∠CAB=60°

∴∠ACB=∠CAD=30°

∴∠BAD=30°

In △ABD,

sin30°=ADBD

⇒BD=ADsin30°=4.5

Therefore,

BC=BC+DC=4.5+9=13.5m