Question

An aeroplane is flying at the height of 300 m above the ground. Flying at this height, the angles of depression of 2 points from the aeroplane on the both banks of the river in opp. direction are 45 and 60. Find the width of the river.

Answer 1

Answer: tan 45° = 300/y

1 = 300/y

y = 300

tan 60° = 300/x

√3 = 300/x

x = 300/√3

x = 100√3

Width of river = x + y

= 300 + 100√3

= 300 + 173.2

= 473.2 m