Question

Standing 5 m apart from a vertical pole of height 3 m, Prabhas observed that the top of a building, situated at the back side of pole, is in line with the top of the pole. If the distance between pole and building is 20 m, estimate the height of the building.
[Here, height of Prabhas is neglected]

• A. 9 m
• B. 10 m
• C. 15 m
• D. 6 m

Answer 1

The correct option is C 15 m


In the figure above, it is assumed that Prabhas is standing at point C, PQ is pole and AB is building.

$\Delta ABC\sim \Delta PQC$ since all the corresponding angles are equal.
$\frac{AB}{PQ}=\frac{BC}{QC}\frac{h}{3}=\frac{25}{5}\frac{h}{3}=\frac{5}{1}h=15m$