Answer:
The width of the garden is 100 feet.
Step-by-step explanation:
The formula for the perimeter of a rectangle is 2(L+W) where L = length and W = width.
Since we know the perimeter (the fence that surrounds the garden) is 820 feet and the length of the pen is 10 feet longer than 3 times its width, we can set an equation and solve for the width:
L = 10 + 3W
So substitute 10 + 3W for L in the equation:
2[(10 + 3W) + W) = 820
2(10 + 4W) = 820
10 + 4W = 410
4W = 400
W = 100
Therefore, the width of the garden is 100 feet.
