Answer:
251.327 in^2
Explanation:
I looked up the equations and plugged in the numbers. The equation for a cylinder is pi × radius squared × height. The equation for the cone was pi × radius squared × the height divided by 3.
I plugged in the numbers and got these equations
Cylinder:

Cone:

As you can see, if you simplify what's in the parentheses, 15÷3=5. The two equations are exactly the same. So are the volumes, so the cone and the cylinder have the exact same volume.