Machine-translated by Google. Questions are authored in English.
Top

Discussion

An aeroplane when 900 m high passes vertically above another aeroplane at an instant when their angles of elevation at same observing point are 60° and 45° respectively. Approximately, how many meters

  • A.231 m
  • B.261 m
  • C.341 m
  • D.381 m

Answer: D

Both aeroplanes lie on the same vertical line, so a single horizontal distance \( d \) serves both sightings.

Upper plane, 900 m high, elevation \( 60^{\circ} \):

\[ d = \frac{900}{\tan 60^{\circ}} = \frac{900}{\sqrt{3}} = 300\sqrt{3} = 519.6 \text{ m} \]

Lower plane, elevation \( 45^{\circ} \):

\[ h = d \tan 45^{\circ} = 519.6 \text{ m} \]

\[ 900 - 519.6 = 380.4 \approx 381 \text{ m} \]

The larger elevation must belong to the higher aircraft, which is what pairs \( 60^{\circ} \) with 900 m.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.