(Q18) A man sees the top of a tower in a mirror which is at a distance of 87.6 m from the tower. The mirror is on the ground facing upwards. The man is 0.4 m away from the mirror and his height is 1.5 m. How tall is the tower?

Ah1.5 m0.4 m87.6 mBETowerCMirror

Solution :

In ∆ABC & ∆EDC

∠ABC = ∠EDC = 90o

∠BCA = ∠DCE (Complements of the angle of incidence and angle of reflection are congruent)

∆ABC ∼ ∆EDC ( by AA similarity)

AB
ED
 =
BC
CD
⇒
h
 =
h =
×
= m

Hence, the height of the towers is m