Heights and Distances Practice Test 1

Question : 9 of 40

Marks: +1, -0

Two poles of equal heights stand on eithersides of a roadway which is 80 m wide. At apoint on the roadway between the pole, theelevation of the tops of the poles are 45° and30°. Find the height of the poles.

$80/{ √3+1}$ m
$40/{ √3+1}$ m
$120/{ √3+1}$ m
All of the above
None of these

Validate

Solution:

In ΔABC,

h/y=\tan45°=1⇒h=y

......(1)
In ΔEDC,

h/{80-y}=1/√3

h={80-y}/√3

......(2)
From equations (1) and (2),

y={80-y}/√3

y=80/{√3+1}

∴h=y= 80/{√3+1}m

Go to Question:

Prev Question

Next Question