What is the formula for the volume of a cylinder? how did you get that? a) v = πr2 h; the area of the circle base times the height of the cylinder b) v = πr2 h; the circumference of the circle base times the height of the cylinder c) v = 2πrh+2πr2; the area of the circle bases plus the area of the unfolded rectangle d) v = 2πrh+2πr2; the circumference of the circle bases plus the area of the unfolded rectangle