1. The problem asks if Kirby's expression for the surface area of a rectangular prism is correct. 2. The formula Kirby gives is: $$\text{Surface area} = 2ab + 2ac + 2bc$$ 3. Recall the surface area formula for a rectangular prism with edge lengths $a$, $b$, and $c$: $$\text{Surface area} = 2(\text{area of front/back}) + 2(\text{area of top/bottom}) + 2(\text{area of left/right})$$ 4. The front and back faces each have area $ab$, so combined area is $2ab$. 5. The top and bottom faces each have area $ac$, so combined area is $2ac$. 6. The left and right faces each have area $bc$, so combined area is $2bc$. 7. Adding these together: $$2ab + 2ac + 2bc$$ 8. This matches Kirby's expression exactly. 9. Therefore, Kirby is correct. **Final answer:** Kirby is right because the formula correctly sums the areas of all six faces of the rectangular prism.