Answer:
Length 70 ft
Width 30 ft
Explanation:
Let L be the length and W the width.
The rectangular field is 40 feet longer than it is wide:
L = W + 40
It takes a total of 200 feet of fencing to enclose it (to surround its perimeter)
L+L+W+W = 200 ------> 2L+2W = 200
Replace the L from the first equation
2(W+40) + 2W = 200 -------> 2W+80+2W = 200 ------>
------> 4W = 200 -80 ------> 4W = 120 ------> W= 120/4 = 30
Now, use the value of W to find L
L = W + 40 ------> L = 30 + 40 = 70
and the dimensions are: length L = 70 ft and width W = 30 ft