Answer:
6ft by 40ft
Step-by-step explanation:
Perimeter = 2(L+W)
Area = LW
L is the length of the fence
W is the width
Given
P = 68ft
A = 240ft²
Substitute into the formula
68 = 2L+2W ... 1
240 = LW... 2
From 1;
34 = L+W
L = 34-W ... 3
Substitute 3 into 2
From 2;
LW = 240
(34-W)W = 240
34W - W² = 240
- W²+34W = 240
W²-34W - 240 = 0
W²+6W-40W - 240 = 0
W(W+6)-40(W+6) = 0
W-40 = 0
W = 40feet
Since
34 = L+W
34 = L + 34
L = 6ft
Hence the dimension of the fence is 6ft by 40ft
