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if each side of a square lot is increased of 4 feet, its area increased by 216
square feet. find the side of the original square lot.
New area - old area = 216 sq/ft
(x+4)^2 - x^2 = 216
x^2 + 8x + 16 - x^2 = 216
Combine like terms
8x = 216 - 16
8x = 216
x = 25 ft is the side of the original square
29^2 - 25^2 =
841 - 625 = 216, confirms our solution