Perimeter

The perimeter of a shape is the total distance around its edge — you find it by adding the lengths of all the sides.

For a rectangle with length $l$ and breadth $b$, opposite sides are equal, so

For a square with side $s$, all four sides are equal, so $P = 4 \times s$.

Worked example. A rectangle is $8$ m long and $5$ m wide: $P = 2 \times (8 + 5) = 2 \times 13 = 26$ m. A square of side $7$ cm has $P = 4 \times 7 = 28$ cm.