Question 145114
YOU HAVE A RIGHT TRIANGLE WITH THE BASE=4M & THE HYPOTENUSE=5M.
4^2+X^2=5^
16+X^2=25
X^2=25-6
X^2=9 
X=SQRT9
X=3M. IS THE HEIGHT OFTHE LADDER ON THE SIDE OF THE WALL.
12-3=9M IS THE DISTANCE FROM THE TOP OF THE LADDER TO THE TOP OF THE WALL.