Question 998383
The perimeter of MNO is equal to the perimeter of square ABCD.
 If the lengths of the sides of the triangle are represented by 4x + 4, 5x - 3, and 17,
 and one side of the square is represented by 3x,
 find the length of a side of the square. 
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Find the perimeter of the triangle
p = (4x+4) + (5x - 3) + 17
combine like terms
p = 9x + 4 - 3 + 17
p = 9x + 18
find the perimeter of the square
p = 4(3x)
p = 12x
perimeters are equal, therefore
12x = 9x + 18
12x - 9x = 18
3x = 18
x = 18/3
x = 6
find the length of the sides of the square
3(6) = 18 
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Confirm this by finding the perimeters of each
the square:
 4(18) = 72
the triangle
p =  (4(6)+4) + (5(6) - 3) + 17
p = (24+4) + (30 - 3) + 17
p = 28 + 27 + 17
p = 72