Answer:
c = 12ft
Step-by-step explanation:
Given that the wall is 9ft from the ground.
Brace nailed to the wall is 15ft.
Note that the brace to the wall will be slant hence it will look like the hypotenus side of a triangle.
The question requires the solution to the distance from the base of the wall to the brace.
Note from Pythagoras theorem
a^2 = b^2+c^2
Where a = 15ft
b = 9ft
Hence, from the base of the wall, the brace will be nailed 9ft
c = ?
15^2 = 9^2+c^2
225 = 81+c^2
225-81 = c^2
144 = c^2
c =√144
c = 12ft
