Perimeter, Area, & Volume

Why This Matters for Nursing: Calculating wound surface area, determining body surface area (BSA) for chemotherapy dosing, or understanding the volume of fluid in containers—geometry has real healthcare applications.

What You Need to Know

• Perimeter: The distance AROUND a shape (1D - measured in units like cm, m)
• Area: The space INSIDE a 2D shape (measured in square units like cm², m²)
• Volume: The space INSIDE a 3D shape (measured in cubic units like cm³, m³)

🧠 Memory Trick

Perimeter = "Perimeter walks the border" (around the edge)

Area = "Area fills the inside" (square units because you're covering a surface)

Volume = "Volume fills the box" (cubic units because you're filling 3D space)

For rectangles: P = 2L + 2W, A = L × W

Key Formulas

Rectangles & Squares

Triangles

Circles

3D Shapes

π ≈ 3.14 (or use 22/7)

✏️ Worked Examples

Example 1: Rectangle Perimeter

Problem: Find the perimeter of a room that is 12 ft by 10 ft.

Step 1 — Remember what perimeter means. Perimeter is the total distance around the outside of a shape — like how much baseboard you'd need to go around a room.

Step 2 — Use the formula. A rectangle has 2 long sides and 2 short sides: P = 2L + 2W.

Step 3 — Plug in numbers. P = 2(12) + 2(10) = 24 + 20 = 44.

Answer: 44 feet