Heights and Distances Practice Test 1

Question : 32 of 40

Marks: +1, -0

The angle of elevation of the top of anunfinished pillar at a point 150 m from itsbase is 30°. If the angle of elevation at thesame point is to be 45°, then the pillar has tobe raised to a height of how many metes?

59.4 m
61.4 m
62.4 m
63.4 m
None of these

Validate

Solution:

Let BC = x metre height of the pillar,
And CD = h metre height of the unfinished pillar.
In ΔABC,

\tan 30°=x/150⇒x=150/√3

And In ΔABD,

\tan ={h+x}/150

⇒1={h+x}/150

⇒150=h+150/√3

[From Eq. (i)]

⇒h={150(√3-1)}/√3

=50√3(√3-1)=63.4m

Go to Question:

Prev Question

Next Question