Polygons with 21 to 99 sides have a different system. Take the prefix for the tens digit (found on the left column), the ones digit (right column below), and then stick a kai between them to get (tens)kai(ones)gon. The 3-digit sided polygons are named in a similar fashion. A 100-sided polygon is called a hectogon.Take the hundreds digit, find it on the column for ones digits, then stick a hecta to its right. Now number off the tens and ones like above: (hundreds)hecta(tens)kai(ones)gon.he 3-digit sided polygons are named in a similar fashion. A 100-sided polygon is called a hectogon. Take the hundreds digit, find it on the column for ones digits, then stick a hecta to its right.