Question

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

Answer 1

Let's find the length of $LN$ in the figure.

Let $MN=18m$ be the flag pole and its shadow be $LM=9.6m$

The distance of the top of the pole,$N$ from the far end, $L$of the shadow is $LN.$

From right-angled $∆LMN$,

$L{N}^2=L{M}^2+M{N}^2$

On applying Pythagoras theorem we obtain

⇒$$\begin{gathered} \Rightarrow L{N}^2={(9.6)}^2+{\left(18\right)}^2\Rightarrow L{N}^2=9.216+324 \\ \Rightarrow L{N}^2=416.16 \\ \Rightarrow L{N}^{}=\sqrt{415.16}=20.4m \end{gathered}$$

Hence, the required distance is $20.4m$