Question

A ladder of $15$ m length reaches a window which is $9$ m above the ground on one side of the street. Keeping its foot at the same point the ladder is turned to the other side of the street and now it reaches a widow $12$ m high. The width of the street is

• A. $21$ cm
• B. $24$ cm
• C. $27$ cm
• D. $29$ cm

Answer 1

Answer: (A)

$21$ cm

Width of street $=AB=AC+BC$

$AC\&BC$ can be calculated by Pythagoras equation

So, $BC=\sqrt{{15}^2-{12}^2}$

$=\sqrt{225-144}$

$=\sqrt{81}$.

$=9m$.

Similarly,

$AC=\sqrt{{15}^2-9^2}$

$=\sqrt{225-81}$

$=\sqrt{144}$

$=12$.

So, width of street $=AC+BC=12+9=21m$