Answer:
9m
Step-by-step explanation:
First of all, I need to asume that the wall is perpendicular to the floor, so we have a right triangle with both the floor (a) and the wall (b) as legs and the ladder as the hypotenuse. This permit us to use Pitgoras' theorem:
a^2 + b^2 = 15^2
As the wall has 12m:
a^2 + 12^2 = 15^2
a^2 + 144 = 225
a^2 = 225 - 144
a^2 = 81
Applying sqr root
a = [tex]\sqrt{81}[/tex]
a = 9
