Question

the angle of elevation of an aeroplane from a point on the ground is 60° after flight of 15 seconds the angle of elevation changes to 30°. If the aeroplane is flying at a constant height of 1500✓3 ( 1500× root3 ). find the speed of aeroplane in km/h

height and distance
trigonometry​

Answer 1

$\huge\colorbox{cyan}{Answer:-}$

Height of aeroplane =BD=CE=1500

3 m and ∠BAE=60° and CAE=30°

In triangle ADB tan60° = AD1500upon 3⇒3

=

AD 1500 upon 3

⇒AD=1500 m

In triangle CAE

tan30° =

AE

1500

3⇒ 3 1 = AD 1500

3

⇒AE=1500×3=4500 m

Distance covered by plane in 15 seconds: BC=DE=AE−AD=4500−1500=3000 m

Speed of aeroplane = 15 upon 3000

=200 m/s=720 km/hr