🧱 See It
Filling a box meant stacking identical rectangular layers. A cylinder (like a soup can) fills exactly the same way — except every layer is a circle instead of a rectangle.
✏️ Draw It
A real cylinder, with its radius and height marked:
The top face is a real circle — that circle is exactly one layer. Stack it up to the cylinder's height to fill the whole shape.
🔢 Write It
Find the round base's area first, then multiply by height — exactly like a box, just with a circle for the base instead of a rectangle:
Volume = (base area) × height
Volume = (3.14 × radius × radius) × height
Two separate steps: find the circle's area first, THEN multiply by height. Never all in one pass.
💡 Worked Examples
Example 1 — radius = 3 cm, height = 10 cm
- Step 1, base area:
3.14 × 3 × 3 = 28.26 cm² - Step 2, multiply by height:
28.26 × 10 = 282.6 - Answer:
Volume = 282.6 cm³
Example 2 — radius = 5 cm, height = 6 cm
- Step 1, base area:
3.14 × 5 × 5 = 78.5 cm² - Step 2, multiply by height:
78.5 × 6 = 471 - Answer:
Volume = 471 cm³
🧠 Quick Reference
Volume of a cylinder = (3.14 × radius × radius) × height. Find the round base's area as its own labeled step first — then multiply by height second.