1. **Problem:** Find the surface area of a square pyramid with base edges 11 in and slant height 20.7 in. 2. **Formula:** Surface area of a pyramid = Base area + Lateral area - Base area for square = $s^2$ - Lateral area = $\frac{1}{2} \times \text{perimeter} \times \text{slant height}$ 3. **Calculate base area:** $$\text{Base area} = 11^2 = 121 \text{ in}^2$$ 4. **Calculate perimeter:** $$\text{Perimeter} = 4 \times 11 = 44 \text{ in}$$ 5. **Calculate lateral area:** $$\text{Lateral area} = \frac{1}{2} \times 44 \times 20.7 = 22 \times 20.7 = 455.4 \text{ in}^2$$ 6. **Calculate total surface area:** $$\text{Surface area} = 121 + 455.4 = 576.4 \text{ in}^2$$ 7. **Answer:** The surface area of the pyramid is **576.4 in²**.