If you mean perimeter, Perimeter is the distance around a two-dimensional shape.
To get the perimeter of a rectangle: 2l + 2w (l is length and w is width)
The perimeter of a square: 4s (s is sides)
The perimeter of a triangle: a+b+c (add all sides)
The perimeter of a circle: Either (2)(pi)(r) or (pi)(d) (pi - 3.14; r - radius; d - diameter)