Cut a 1.2m cylinder steel into three sections, and increase its surface area by 6.28 square decimeters?

Cut a 1.2m cylinder steel into three sections, and increase its surface area by 6.28 square decimeters?

1.2 m = 12 decimeters, 6.28 △ 4 = 1.57 (square decimeters), 1.57 × 12 = 18.84 (cubic decimeters); answer: the original volume of this steel is 18.84 cubic decimeters