Perimeter is the total distance around the outside of a shape. To find it, add up the lengths of all the sides.
Perimeter is measured in units (not square units). Think of walking around the outside edge of the shape.
On a grid, each square usually represents one unit. To find perimeter, count the number of unit lengths around the shape.
Be careful not to count any inside lines—only the outer edges count toward the perimeter.
Look at how perimeter is found by counting units around shapes placed on a grid.
If a side is longer than one unit, count carefully to include each unit along that side.
Use these strategies to avoid mistakes while finding perimeter on grids.
Perimeter measures the boundary. It is different from area, which measures space inside a shape.