Answer:
11.3 ft
Explanation:
We have a right triangle with the hypotenuse of 12 and a leg of 4
Using the pythagorean theorem
a^2 +b^2 = c^2
4^2 + b^2 = 12^2
16 +b^2 = 144
Subtract 16 from each side
b^2 =144-16
b^2 =128
Taking the square root of each side
sqrt(b^2) = sqrt( 128)
b =11.3137085