That depends on exactly what you want to 'do' to it or with it. Do you want to calculate it ? Spell it ? Define it ? Walk around it ? Send it in Morse Code ? The perimeter of an area or object is the...
in math terms, the perimeter is the measure around the shape.
Perimeter is a term applied to the boundary of a shape or object. It is the distance around the outside of it. A link is provided below.
If you know the perimeter, there is no need to find it again.