This document discusses calculating perimeters of basic shapes like squares, rectangles, and triangles. It provides formulas for calculating each: the perimeter of a square is 4 times the length of one side; the perimeter of a rectangle is the sum of the lengths of all four sides; the perimeter of a triangle is the sum of the lengths of its three sides. It notes that complex shapes may require calculating the perimeters of individual components and summing them.