Question

QUESTION: 1.the angle of elevation of a bird from a point 50m above a lake is 30degree and angle of depression of its reflection in the lake is 60degree find the height of bird above the lake

Answer 1

Step-by-step explanation:

this is correct answer 100

Answer 2

Bird is at the height of 100m from lake

•Let bird is at h metre above the

lake

=> AD = h

•also, AD = CD=h , because distance of image should same as distance of object.

•Given , BD = 50m

EB = d ______(say)

•Now , In triangle ABE

tan 30° = P/B = AB/BE = (h-50)/d

1/√3 = (h-50)/d

d = √3(h-50) ______(1)

•Now , In triangle CBE

tan 60° = P/B = CB/BE = (h+50)/d

√3 = (h+50)/d

•Putting value of d from (1)

√3 = (h+50)/√3(h-50)

3 = (h+50)/(h-50)

3(h-50) = h+50

3h -150 = h +50

3h-h = 200

2h = 200

h = 100 m

•Bird is at the height of 100m from lake