12.

# Perimeter - Missing Side Lengths - 3rd Grade Math

Find the missing side lengths in polygons, given their perimeter. For regular polygons, this operation can be related to division. For example, if a regular hexagon has a perimeter of 36, the side length is 36 ÷ 6 = 6.

### Common Core Alignment

**3.MD.8**Solve 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.