Question

A vertical pole of height $5.60m$ casts a shadow of length $3.20m$ on the horizontal earth surface. Under the similar conditions and at the same time, find the length of the shadow cast by another vertical pole of height $10.5m$.

Answer 1

The length of shadow is directly proportional to the height of the vertical pole.
Let $a$ be the length of the shadow cast by the pole of height $10.5m$.
So, $5.60:10.5=3.2:a$
Applying the rule, product of extremes $=$ product of means

$5.6\times a=10.5\times 3.2$

$a=\frac{10.5\times 3.2}{5.6}$

$a=6$

Hence, the length of shadow cast by the pole of height $10.5m$ is $6m$.