Question

then find the height of the U
A wire of length 18 m had be
the ground. Because it
Flength 18 m had been tied with electric pole at an angle of elevation 30° with
ind. Because it was convering a long distance, it was cut and tied at an angle of
ation 60° with the ground. How much length of the wire was cut?
11
from the foot of the tower is 30° and the

Answer 1

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First, sinA=P/H

here, sin30=1/2

H=18 m

so,P/H=1/2

or,P=H/2=9 m

In second case, the length of the pole i.e. P=9 m will be the same.

sin60=√3/2=P/H

here we have to find H.

so,H=(9x2)/√3

      =18/√3

      =(18x√3)/3

      =6x√3=6x1.72(approx.)=10.32

so, new length=10.32

so,decrease in length=18-10.32 m=7.68 m.

Here,P is the perpendicular & H is the hypotenuse of a right angled triangle which

is formed by the above arrangements. The right angle is formed at the point where the pole meets the ground.This method has strictly been done in accordance with the formulas of trigonometric standard angles' values.

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