Question

as observed from the top of the Lighthouse 100 metre high above sea level the angle of depression ship sailing directly to a date change from the 30 to 60 find the distance travelled by the ship during the period of observation

Answer 1

Hey Sona

Its from 10th

Height = AB= 100
BC= x
CD=y

triangle ABC
tan60= AB/BC
√3= 100/x
x= 100/√3

In triangle ABD
tan30= AB/CD
1/√3= 100/y
y= 100√3

as we know 
BD=BC+ CD
y= x+ CD
CD= y-x
putting the values we get

CD= 100 x (3-1) /√3 
=100 x 2/√3
=200/√3