Practice finding perimeter of polygons with unequal side lengths. Students begin with adding up the side lengths to find the perimeter. For non-regular shapes, students can look for patterns to quickly calculate the perimeter. For example, in rectangles the opposite sides are equal; therefore, they add the two side lengths and double, to get the perimeter.

Common Core Alignment

3.MD.8Solve real world and mathematical problems involving perimeters of polygons, including finding the perimeter given the side lengths, finding an unknown side length, and exhibiting rectangles with the same perimeter and different areas or with the same area and different perimeters.