The perimeter of the new sheet is 720 feet.
Let the old length = x and the width= y.
So, periemeter = 2(x + y) = 120 or, x + y = 60 or, y = 60 - x .......(1)
Area = xy = 800.
Plug y = 60 - x and solve for x.
[tex]x(60-x)=800\\60x-x^2=800\\x^2-60x+800=0\\(x-20)(x-40)=0\\x=20, 40\\[/tex]
For x = 20, y = 60 - 20 = 40.
For x = 40, y = 60 - 40 = 20.
So dimensions are 20 ft and 40 ft.
If The length and width of the rectangular sheet of metal are each multiplied by 6.
So the new dimensions are (20*6) = 120 ft and (40*6) = 240 ft.
So the perimeter is = 2(120 + 240) = 720 ft.
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