1. **Problem:** Find the surface area of the L-shaped prism with edges 12 yd, 11 yd vertically, 3 yd along top, and two 4 yd segments horizontally. 2. **Formula:** Surface area of a prism is the sum of the areas of all its faces. For an L-shaped prism, break it into rectangles and sum their areas. 3. **Step-by-step:** - Calculate areas of each rectangular face using $\text{Area} = \text{length} \times \text{width}$. - Sum all areas. 4. **Intermediate work:** - Bottom rectangles: $12 \times 3 = 36$ yd$^2$, $4 \times 4 = 16$ yd$^2$ - Vertical faces: $11 \times 3 = 33$ yd$^2$, $11 \times 4 = 44$ yd$^2$ - Top faces: $12 \times 4 = 48$ yd$^2$ - Add all: $36 + 16 + 33 + 44 + 48 = 177$ yd$^2$ 5. **Answer:** The surface area is $177$ yd$^2$. This method applies similarly to other L-shaped prisms by breaking them into rectangles and summing areas.