What is the volume of a cylinder? give an informal argument for the formula.
a) v = πr2h; a cylinder has a circle base and top; the middle can be unwrapped to a rectangle.
b) v = πr2h; a cylinder is like a stack of circles, so it's the area of the circles times the height.
c) v = 2πr2 + 2πrh; a cylinder has a circle base and top; the middle can be unwrapped to a rectangle.
d) v = 2πr2 + 2πrh; a cylinder is like a stack of circles, so it's the area of the circles times the height.