If you want to know what perimeter is than READ THIS ARTICLE!!!
Perimeter is the outside of an object and you use a ruler to find out how long the length of each side is and then add them up to find the total perimeter.
There are lots of different strategies you could use like,division,multiplication,repeated addtion and guess and check when you have to construct a shape with a given perimeter.
So thats the definition of what perimeter means!!!