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SSC CPO 2020 PYQ — Question 133

SSC CPO - 23 Nov 2020 - Shift 2 • Quantitative Aptitude • Q133

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The length of the shadow of a vertical pole on the ground is 18 m. If the angle of elevation of the sun at that time is θ, such that cosθ = 1213\frac{12}{13}, then what is the height ( inm ) of the pole ?

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Correct answer: A

Explanation

The correct answer is option 1 i.e. 7.5

The length of the shadow of a vertical pole on the ground = 18 m

 cosθ = Base/Hypotenus = 1213\frac{12}{13} = BC/AC

BC = 12x , and AC = 13x

Use Pythagoros theorem in triangle ABC :

AC2 = BC2 + AB2

(13x)2 = (12x)2 + h2

169x2 - 144x2 = h2

h = 5x

We have given, BC = 18 = 12x

⇒ x = 3/2

So, h = 5x = 5 × 3/2 = 7.5