Afarmer has a rectangular field that is 100 yards long by 20 yards wide. what is the total area of the field?

The area of the field is equal to the area of rectangular
a = l × w

Given:
l = 100 yards
w = 20 yards

Solution:
put the numbers to the formula
a = l × w
a = 100 × 20
a = 2,000
The area of the field is 2,000 square yards

A farmer has a rectangular garden plot surrounded by 200 ft of fence. Find the length and width of the garden if its area is 2400 square feet.
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Let x = width
and y = length
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The because he has 200 ft of fencing, this must lest than or equal to the perimeter:
2(x+y) = 200
x+y = 100
Solving for x:
x+y = 100
x = 100-y