What is the length of the side of a right triangle that has a side length of 12 ft and hypotenuse that measures 15 ft

9 ft

Step-by-step explanation:

The Pythagorean theorem states

a^2+b^2 = c^2 where a and b are the legs and c is the hypotenuse

Substituting in what we know (one leg is 12 and the hypotenuse is 15)

12^2 + b^2 = 15^2

144 + b^2 = 225

Subtract 144 from each side

144-144 + b^2 = 225-144

b^2 = 81

Take the square root of each side

sqrt (b^2) = sqrt (81)

b = 9