Question

When a plane mirror is placed horizontally on a level ground at a distance of 60m from the foot of a tower, the top of the tower and its image in the mirror subtend an angle of 90° at the eye. The height of the tower will be(a) 30m(b) 60m(c) 90m(d) 120m

Answer 1

answer : option (b)

explanation : when a plane mirror is placed horizontally on a level ground at a distance of 60m from the top of tower as shown in figure.

a/c to question, The top of tower and its image in the mirror subtend an angle of 90° at the eyes.

so, angle made by top of tower and horizontal line is 45° as shown in figure.

so, tan45° = h/60

h = 60m hence, the height of tower is 60m

Answer 2

Answer:

Explanation:

Given inΔABC from the diagram

tan45°=h60

h=60 m