An electric pole is 10 m high. A steel wire tied to the top of the pole isaffixed at a point on the ground to keep the pole upright. If the wiremakes an angle of 45º with the horizontal through the foot of the pole,find the length of the wire.


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Given:

Height of the electric pole, h = AB = 10 m

Angle of elevation, θ = 45°

To find: Length of the wire, AC

Solution:

Let AB be the height of the electric pole and AC be the length of the wire.


In right angled Δ ABC,

cosec θ = [Hypotenuse] / [Opposite]


cosec 45° = AC/AB

Here θ = 45°

And also the opposite side is AB and the hypotenuse side is AC


AC = AB cosec 45°

Here AB = 10 m

= 10 × (√ 2) m


= 10 × 1.414 m


= 14.14 m


Therefore the length of the wire is 14.14 m.

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