Cut off the square of 10 cm in length at the four corners of a rectangular piece of iron which is twice the length and width, and then fold up the four sides to make a box without a cover His volume is 4000cm square, and the length and width of the rectangular iron sheet are calculated

Cut off the square of 10 cm in length at the four corners of a rectangular piece of iron which is twice the length and width, and then fold up the four sides to make a box without a cover His volume is 4000cm square, and the length and width of the rectangular iron sheet are calculated

Set width X
(2X-20)(X-20)×10=4000
(X>0)
x=30
X = 0 (rounding)
Length: 60cm
Width 30cm

There is a rectangular sheet of iron 16 cm in width. After subtracting the square 4 cm in length from the four corners, it is welded into a box without a cover. This box is known
Its volume is 786 cubic centimeters. What is the surface area of this sheet of iron

786 divided by 8 divided by 4 = 18
(18x4 + 18x16 + 16x4) divided by 2 = 212
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