If you have ever seen a pinball machine, you would know that it is shaped like a rectangular box. Since a rectangle has two sets of equal parallel lines, then you would have to know the length and the width. Its perimeter is equal to the total length of all sides. Thus, the equation is 2L + 2W = 172 inches. However, since there is no other data other than the perimeter, I can't give a definite numerical answer. The only answer I could give is in variables. Thus, the length of the pinball machine is
2L = 172 - 2W
L= 86 - W