1. The problem is to find the formula for the perimeter of a shape. 2. The perimeter is the total distance around the boundary of a two-dimensional shape. 3. For common shapes, the perimeter formulas are: - Square: $$P = 4s$$ where $s$ is the length of one side. - Rectangle: $$P = 2(l + w)$$ where $l$ is length and $w$ is width. - Triangle: $$P = a + b + c$$ where $a$, $b$, and $c$ are the lengths of the sides. 4. The key rule is to add the lengths of all sides to get the perimeter. 5. For example, if a rectangle has length 5 and width 3, then its perimeter is $$P = 2(5 + 3) = 2 \times 8 = 16$$. 6. This formula applies to any polygon by summing all side lengths.