Ivor has many ways to place 4 identical 3 cm × 3 cm squares together as follow:

Among these figures, compare the perimeters of all the figures. Which figure’s perimeter is the longest? Answer 1, 2, 3, or 4.

The perimeter of (1) is the longest because none of the squares share sides with one another. The total perimeter of the figure is 3 × 4 × 4 = 48 cm.

In general, the less shared segments that a figure has, the longer its perimeter, as you will find out in the rest of this section.