A cylindrical tin bucket without a cover is 24 cm high and the bottom radius is 10 cm. How many square centimeters of tin do you need to make this bucket? (the total number is 100 square centimeters.)

A cylindrical tin bucket without a cover is 24 cm high and the bottom radius is 10 cm. How many square centimeters of tin do you need to make this bucket? (the total number is 100 square centimeters.)

2 × 3.14 × 10 × 24 + 3.14 × 102, = 3.14 × 480 + 3.14 × 100, = 3.14 × 580, ≈ 1800 (square centimeter); answer: to make this tin bucket, use 1800 square centimeter iron sheet

A cylindrical bucket made of iron sheet without cover. The circumference of the bottom is 12.56 decimeters and the height is 4 decimeters
1. How many square decimeters of iron sheet does it take to make this bucket?
2. How many kilograms of water can this bucket hold at most? (1 cubic decimeter weighs 1 kilogram)

Bottom radius: 12.56/3.14/2 = 2 decimeters
1. How many square decimeters of iron sheet does it take to make this bucket?
3.14 * 2 * 2 + 12.56 * 4 = 62.8 square decimeters
2. How many kilograms of water can this bucket hold at most? (1 cubic decimeter weighs 1 kilogram)
3.14 * 2 * 2 * 4 = 50.24 cubic decimeter
1 * 50.24 = 50.24kg

Make a cylindrical tin bucket without cover, 40 cm high and 10 cm bottom radius
(1) How much metal does it take to make this bucket?
(2) What's the capacity of this bucket?

(1) Bottom 3.14 * 10 * 10 = 314 (cm2)
Side 3.14 * 10 * 2 * 40 = 2512 (cm2)
Total iron sheet 314 + 2512 = 2826 (cm2)
(2) 3.14 * 10 * 10 * 40 = 12560 (cubic centimeter) = 12.56 (cubic decimeter) = 12.56 (liter)