RRB NTPC Mains or Stage 2 Model Paper 8 with solutions

Question : 24 of 120

Marks: +1, -0

From the top of a cliff 200 m high, the angles of depression of the top and bottom of a tower are observed to be 30º and 45º, respectively. What is the height of the tower?

400 m
$400√ 3$ m
$400/ √3$ m
None of these

Validate

Solution:

In ΔACB, tan 30º

= {200 -h}/x=1 /√3

= {500 - h }/x

⇒ x = (200 - h) √3

... (i)
In ΔADE,
tan

45º = 200/ x

⇒ 1 = 200/ x ⇒ x = 200 m

From Eq. (i)

200 = (200 – h) √3

⇒ h = 200 [{√3 -1 }/√3] m

Go to Question:

Prev Question

Next Question