24.84÷2= 12.42

Note: After the rectangular iron sheet is rolled into a cylindrical shape (left and right), the circumference of its bottom surface is equal to the circumference of a circle.

Circular radius

12.42÷π÷2=6.2 1/π

As can be seen from the figure, the height of the oil drum =4 radii.

So the height =6.2 1/π x4=24.84/π.

Transverse area (rectangular area) = 12.42x 24.84/π.

The area of two circles = π x (6.2 1/π) 2.

The required iron sheet is the side area+the area of 2 circles.

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