Perimeter is the total distance around the outside of a shape. Each shape has its own formula.
P = 2 × (width + height)
Example: 5 × 3 rectangle → P = 2 × (5 + 3) = 16.
P = side a + side b + side c
Example: 3 + 4 + 5 = 12.
C = 2πr (where r is the radius)
Example: r = 5 → C = 2 × 3.14159 × 5 ≈ 31.42.
Fencing, framing, baseboards, fabric trim, landscaping borders — anything that runs along the edge of a shape.