Make a cylindrical tin bucket without cover, with a bottom diameter of 20 cm and a height of 27 cm. How many square centimeters of tin do you need to make this bucket? (the total number is 100 square centimeters.)

Make a cylindrical tin bucket without cover, with a bottom diameter of 20 cm and a height of 27 cm. How many square centimeters of tin do you need to make this bucket? (the total number is 100 square centimeters.)

3.14 × 20 × 27 + 3.14 × (20 ÷ 2) 2, = 62.8 × 27 + 3.14 × 102, = 1695.6 + 314, = 2009.6 (square centimeter), ≈ 2000 square centimeter; answer: to make this bucket, use iron sheet 2000 square centimeter

To make a cylindrical tin bucket without cover, the bottom diameter is 10 cm and the height is 20 cm. At least how many square centimeters of tin is needed?

3.14×10×20+3.14×（10÷2）²

Mathematics homework: do a cylindrical bucket without a cover, the bottom diameter is 6 decimeters, 8 decimeters high, at least how many square decimeters of iron sheet? Volume?

Surface area: 2 * π * 6 * 8 + π * 6 * 6 = 414.69 square decimeters
Volume: π * 6 * 6 * 8 = 904.78 cubic decimeter