SOLUTION: the area of a square is 77 more than the perimeter. Find the length of a side

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Question 861223: the area of a square is 77 more than the perimeter. Find the length of a side
Answer by ben720(159) About Me  (Show Source):
You can put this solution on YOUR website!
Let s = side, s%5E2 = area, 4s = perimeter
the area of a square is 77 more than the perimeter
s^2 is 77 more than 4s
s%5E2=4s%2B77
Subtract 4s+77 from both sides
s%5E2-4s-77=0
Use the quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%284+%2B-+sqrt%28+4%5E2-4%2A1%2A-77+%29%29%2F%282%2A1%29+
x+=+%284+%2B-+sqrt%28+16%2B308+%29%29%2F%282%29+
x+=+%284+%2B-+sqrt%28+324+%29%29%2F%282%29+
x=%284%2B18%29%2F2 OR x=%284-18%29%2F2
x=11 OR x=-7
Because the length can't be negative, it's 11.