Question

A ladder is placed in such a way that its foot is at a distance of 15m from a wall and its top reaches a window 20m above the ground. Find the length of the ladder. 

Answer 1

Let the height of the window from the ground and the distance of the foot of the ladder from the wall be AB and BC, respectively.
We have :  

AB = 20 m and BC = 15 m
Applying Pythagoras theorem in right-angled ABC, we get:  

 

`AC^2=AB^2+BC^2` 

`⟹AC= sqrt(20^2+15^2)` 

`=sqrt(400+225)` 

`=sqrt625` 

=25 m 

Hence, the length of the ladder is 25 m.