Question

A $15m$ long ladder reached a window $12m$ high from the ground on placing it against a wall . Find the distance of the foot of the ladder from the wall .

Answer 1

In the given figure, suppose $AC$ is the ladder and $BC$ is the height of the wall from the ground and $AB$ is the distance of the foot of ladder from the wall, then

Using Pythagoras theorem in $△ABC$,

$A{C}^2=A{B}^2+B{C}^2$

${15}^2=A{B}^2+{12}^2$

$A{B}^2=225-144$

$A{B}^2=81$

$AB=9m$

Hence, the distance of the foot of ladder from the wall is $9m$.