A common characteristic for the shapes given is that they all consist of sides. Therefore, the most applicable sorting rule is the number of sides. In this regard, there will be two categories of the shapes given.
That is, number of sorting rule in which:
Category 1: 1 square and 1 rectangle all with four sides.
Category 2: 1 triangle with three sides.
Well lets see. You have a total of 52 marbles. So all you would have to do would be to find the percent of 52 out of 60. This sounds confusing and I may not be completely right but I hope you give it a shot!
