1. **State the problem:** Find the surface area of a cone with diameter 8 cm and slant height 13.6 cm. 2. **Formula:** The surface area $A$ of a cone is given by $$A = \pi r^2 + \pi r l$$ where $r$ is the radius of the base and $l$ is the slant height. 3. **Identify values:** - Diameter $d = 8$ cm, so radius $r = \frac{d}{2} = \frac{8}{2} = 4$ cm. - Slant height $l = 13.6$ cm. 4. **Calculate the base area:** $$\pi r^2 = \pi \times 4^2 = \pi \times 16 = 16\pi$$ 5. **Calculate the lateral surface area:** $$\pi r l = \pi \times 4 \times 13.6 = 54.4\pi$$ 6. **Calculate total surface area:** $$A = 16\pi + 54.4\pi = (16 + 54.4)\pi = 70.4\pi$$ 7. **Approximate using $\pi \approx 3.1416$:** $$A \approx 70.4 \times 3.1416 = 221.2$$ 8. **Round to nearest whole number:** $$\boxed{221} \text{ cm}^2$$ **Final answer:** The surface area of the cone is approximately 221 cm².