Question

A standing pole 20 meters in length casts a shadow of 30 meters. What will be the height of a tower if the shadow cast by the tower is 1,260 meters long?

• A. 760 meters
• B. 820 meters
• C. 800 meters
• D. 840 meters

Answer 1

The correct option is D 840 meters

Given, 30 meters long shadow is cast by a pole of length 20 meters.

We know that longer the shadow is, longer is the object.

$\text{Length of the object}\left(x\right)\propto \text{Length of shadow}\left(y\right)$
$\therefore \frac{x_1}{y_1}=\frac{x_2}{y_2}$

Given,
$x_1=20\text{meters}$
$y_1=30\text{meters}$
$y_2=1260\text{meters}$
$\text{and}{x}_2=\text{height of the tower}$

$\Rightarrow x_2=\frac{x_1\times y_2}{y_1}$
$\Rightarrow x_2=\frac{20\times 1260}{30}$
$\Rightarrow x_2=840\text{meters}$