Question

A $15m$ long ladder is leaning against the wall of a house, touching the window at a height of $12m$ from the ground. How far is the foot of the ladder from the wall of the house (in $m$)?

• A. 9

Answer 1

The correct option is A 9
According to the question, we are given the height of the right triangle and the length of the hypotenuse. We must find the length of its base.
The following diagram depicts the above described scenario.

Applying the Pythagorean Theorem, we know that, in any right triangle,
$hypotenus{e}^2=bas{e}^2+heigh{t}^2$
Hence,
${15}^2=bas{e}^2+{12}^2$
$225=bas{e}^2+144$
$bas{e}^2=225-144$
$bas{e}^2=81$
$base=\sqrt{81}$
$base=9m$