1. The problem asks for the surface area of a cube with side length 15 inches. 2. The formula for the surface area $S$ of a cube with side length $a$ is: $$S = 6a^2$$ This is because a cube has 6 faces, each a square with area $a^2$. 3. Substitute $a = 15$ into the formula: $$S = 6 \times 15^2$$ 4. Calculate $15^2$: $$15^2 = 225$$ 5. Now multiply: $$S = 6 \times 225$$ 6. Calculate the product: $$S = 1350$$ 7. Therefore, the surface area of the cube is $1350$ square inches.