Question

From a point,36 metre above the surface of a lake,the angle of elevation of a bird is obserbed to be 30degree and the angle of depression of its image in the water of lake is obserbed to be 60 degree. Find the actual height of the bird above the lake

Answer 1

Answer:

The actual height of the bird

above the surface of the lake is 48m.

• Let P be the point 36 m above the surface.

• L be the point on the lake(image of bird) at which angle of declination is 60°

• B be the point at which bird is present and angle of inclination is 30°

• Let M be a point on the line joining B and L such that PM is parallel to ground.

• So ML is also 36 m.

•Now, tan 60°= ML/PM

•√3 = 36/PM

• PM = 36/√3

• PM = 12√3

•Now, tan 30° = BM/PM

• 1/√3 = BM /(12√3)

• BM =12

•So total height = BM + ML

= 12 + 36

=48 m

Step-by-step explanation:

here is the image below in the attachment

i have drawn it roughly you can give it names as per your convenience