Posted by **Preston** on Wednesday, January 24, 2007 at 6:38pm.

If two sides of a square field were incresed by three feet the area of the field would increase by 129 square feet. find the area of the original field.

If two sides of a square field were incresed by three feet the area of the field would increase by 129 square feet. find the area of the original field.

Let x be the side of the original square field.

Then, (x + 3)^2 - x^2 = 129

x^2 + 6x + 9 - x^2 = 129

6x = 120 making x = 20.

Therefore, the area of the original square is 20^2 == 400 sq. ft.