Tim needs 40ft fencing.
For fencing the square garden we need to ascertain perimeter of the square.
Perimeter of plot = 2*(a+b)
Where a = length of the plot
b=width of plot
length =12ft
width=8ft
Perimeter of plot = 2*(a+b) = 2*(12+8)ft=40ft
He needs 40ft fencing.
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