Answer:
81 feet
Step-by-step explanation:
Use the Pythagorean theorem: [tex]a^{2} + b^{2} = c^{2}[/tex]
a,b and c are referring to the sides of the triangle; c is the hypotenuse.
[tex]15^{2} - 12^{2} = 9^{2} = 81[/tex]
