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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