Math, asked by subhashree8106, 4 months ago

The angle of elevation of an aeroplane from a point A on the ground is 60° . After a flight of 15 seconds, the angle of elevation changed to 30° . If the aeroplane is flying at a constant height of 1500 √3 m, find the speed of the plane in km/hr. OR At a point A, 20 metre above the level of water in a lake, the angle of elevation of a cloud is 30°. The angle of depression of the reflection of the cloud in the lake, at A is 60° . Find the distance of the cloud from A ? ​

Answers

Answered by kinjal80shah
2

Answer:

Height of aeroplane =BD=CE=1500

3

m and

∠BAE=60

0

and CAE=30

0

In triangle ADB

tan60

0

=

AD

1500

3

3

=

AD

1500

3

⇒AD=1500 m

In triangle CAE

tan30

0

=

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

3000

=200 m/s=720 km/hr

solution

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