Multiple choice

An aeroplane is observed to be approaching the airport. It is at a distance of 10 km from the point of observation on the ground and makes an angle of elevation θ. If the aeroplane is at a height of 8 km above the ground, then which one of the following is correct?

  1. 0 < θ < 30°

  2. 30° < θ < 45°

  3. 45° < θ < 60°

  4. 60° < θ < 90°
Reveal answer Fill a bubble to check yourself
C Correct answer
AI explanation

The right triangle formed has a hypotenuse of 10 km and an opposite side of 8 km. Using trigonometric ratios, sin θ equals the opposite side divided by the hypotenuse, giving sin θ = 0.8. The angle whose sine is 0.8 is approximately 53.13 degrees. Because 53.13 degrees falls between 45 degrees and 60 degrees, the correct range is 45° < θ < 60°.

Keep practicing — related questions