1. The problem is to find the perimeter of a shape. 2. The perimeter is the total distance around the shape, calculated by adding the lengths of all its sides. 3. The formula for the perimeter depends on the shape. For example, for a rectangle, the perimeter $P$ is given by: $$P = 2(l + w)$$ where $l$ is the length and $w$ is the width. 4. For a square, since all sides are equal, the perimeter is: $$P = 4s$$ where $s$ is the length of one side. 5. For a triangle, the perimeter is the sum of the lengths of all three sides: $$P = a + b + c$$ where $a$, $b$, and $c$ are the side lengths. 6. To solve a specific problem, identify the shape and measure or use the given side lengths. 7. Add all side lengths according to the formula for that shape to find the perimeter. This explanation covers the general approach to finding the perimeter of common shapes.