Area=height times base (for some prisms including cylinders)
vcylinder=hpir²
h=height
therefor pir²=base area
vcylinder=height times aeraofbase
given
h=9
v=324pi
324pi=9(basearea)
divide both sides by 9
36pi=areabase
the area of the base is 36pi square cm (put 36 in the blank since the pi is already there)
1. Undo
2 Subtraction
3. Multiplication
4. Solving, both, equal
5. Solve, isolate