First you need to find the area of the circle (the bottom of the cylinder):
8*8*3.14 = 200.96 cm^2
Then to find the volume of the cylinder, multiply the area of the circle by the height of the cylinder which in this case is 15 cm:
200.96*15= 3,014.4 cm^3
Which can just be rounded to 3,014 cm^3 (nearest whole number)