A flag pole 18 m high casts a shadow 9.6 m long. Find the distance of the top of the pole from the far end of the shadow.

Options

A. `21.4`m
B. `20.4`m
C. `30.4`m
D. `40.4`m

Answer

B

Explanation

Let BC=18 m be the flag pole and its shadow be AB=9.6 m. The distance of the top of the pole, C from the far end i.e., A of the shadow is AC.

In right angled `DeltaABC`, `AC^(2)=AB^(2)+BC^(2)` [by Pythagoras theorem]
`rArr AC^(2)=(9.6)^(2)+(18)^(2)`
`AC^(2)`=92.16+324
`rArr AC^(2)=416.16`
`therefore AC=sqrt(416.16)=20.4cm`
Hence, the required distance is 20.4 m.