Question

A ladder $15m$ long reaches a window which is $9m$ 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 to reach a window $12m$ high.

Answer 1

R.E.F image

So $△$CDE

CD=15 cm DE=9 m

using Pythagoras therm,

CE=$\sqrt{C{D}^2-D{E}^2}=\sqrt{225-81}=\sqrt{144}$

=12m

SO $△$ABC,

AB=12 M

AC=15CM

BC=$\sqrt{A{C}^2-A{B}^2}=\sqrt{225-144}=\sqrt{81}=9m$

$\therefore$ BE = 12 + 9 = 21 m