Question

a ladder o length 13 m was kept at a distance of 5 m from the building reach a window on a at what building height is the window from the ground

Answer 1

here we use Pythagoras theorem  

where height of the building is perpendicular

h^2=b^2+p^2  

now here  

h= length of the ladder and  

b=distance between ladder and building

p^2=169-25

=144

p=12