Use iron sheet to make a cuboid bucket without cover, which is 4 decimeters long and 0.5 meters wide and 0.5 meters high. (1) how many square decimeters of iron sheet does it take to make a pair of oil barrels?

Use iron sheet to make a cuboid bucket without cover, which is 4 decimeters long and 0.5 meters wide and 0.5 meters high. (1) how many square decimeters of iron sheet does it take to make a pair of oil barrels?

0.5 M = 5 decimeters
(4 × 4 + 4 × 5 × 4) × 2 = 192 square decimeters

How many square decimeters of iron sheet do you need at least for a cylindrical open bucket with a bottom radius of 4 decimeters and a height of 6 decimeters? (take the approximate value by the method of entering one, and keep the whole number)

3.14 × 4 × 2 × 6 + 3.14 × 42, = 3.14 × 48 + 3.14 × 16, = 3.14 × 64, ≈ 201 (square decimeter); answer: at least 201 square decimeter iron sheet is required

How many square decimeters of iron sheet do you need at least for a cylindrical open bucket with a bottom radius of 4 decimeters and a height of 6 decimeters
(keep integer)

Sheet iron = 4 × 4 × 3.14 + 2 × 4 × 3.14 × 6 = 200.96 square decimeter ≈ 201 square decimeter