JEE Main 2021 · 24 Feb · Shift 1 · Mathematics Q79

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MathematicsSingle correct+4 / -1Question 79 of 90

Two vertical poles are 150 m apart and the height of one is three times that of the other. If from the middle point of the line joining their feet, an observer finds the angles of elevation of their tops to be complementary, then the height of the shorter pole (in meters) is :

20\sqrt3

25\sqrt3

Answer and worked solution

Official answer: D

Complementary angles. $\tan\alpha\tan\beta=1$ : $\frac h{75}\cdot\frac{3h}{75}=1$ , so $h^2=1875$ , $h=25\sqrt3$ m.

(D)

Topics:Heights and distances

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JEE Main 2021 · 24 Feb · Shift 1, Mathematics question 79