Answer:
9 ft
Explanation:
The ladder is 15 feet long
The wall is 12 feet high
Therefore the distance between the base of the wall and the ladder can be calculated by applying phythagoreans theory
c^2= a^2 + b^2
15^2 = a^2 + 12^2
225= a^2 + 144
225-144= a^2
a^2= 81
a= 9 ft