In this module, you can study the meaning of "perimeter" and how to find the perimeter of a square, rectangle or triangle.
The perimeter of a rectangle is NOT the length times the width. (That's the area, not the perimeter.)
You do not find perimeter by counting squares around the outside of the shape.
Study and practice
Use these search terms to find additional resources:
how to measure perimeter
perimeter of square
perimeter of rectangle
perimeter of triangle