1. **State the problem:** Find the surface area of a cylinder with diameter 30 cm and height 40 cm, using $\pi = 3.14$ and no rounding. 2. **Recall formulas:** - Area of a circle: $$a = \pi r^2$$ - Surface area of a cylinder: $$SA = 2 \times \text{area of base} + \text{lateral area}$$ - Lateral area (rectangle wrapped around): $$= 2 \pi r h$$ 3. **Calculate radius:** $$r = \frac{\text{diameter}}{2} = \frac{30}{2} = 15\text{ cm}$$ 4. **Calculate area of one circle (base):** $$a = 3.14 \times 15^2 = 3.14 \times 225 = 706.5\text{ cm}^2$$ 5. **Calculate area of both circles:** $$2 \times 706.5 = 1413\text{ cm}^2$$ 6. **Calculate lateral area (rectangle):** $$= 2 \times 3.14 \times 15 \times 40 = 2 \times 3.14 \times 600 = 3768\text{ cm}^2$$ 7. **Calculate total surface area:** $$SA = 1413 + 3768 = 5181\text{ cm}^2$$ **Final answers:** - Both Circles: 1413 cm² - Rectangle: 3768 cm² - Total Surface Area: 5181 cm²