1. **Problem Statement:** Find the missing value of Surface area ÷ Volume for a cube stack with 27 cubes. 2. **Given Data:** - Number of cubes: 1, 8, 27 - Surface areas: 6, 24, 54 - Volumes: 1, 8, 27 - Surface area ÷ Volume: 6, 3, ? 3. **Formula and Explanation:** For a cube stack made of $n^3$ small cubes (where $n$ is the side length in cubes), - Volume $V = n^3$ - Surface area $S = 6n^2$ The ratio is: $$\frac{S}{V} = \frac{6n^2}{n^3} = \frac{6}{n}$$ 4. **Calculate missing value:** For 27 cubes, $n = \sqrt[3]{27} = 3$. So, $$\frac{S}{V} = \frac{6}{3} = 2$$ 5. **Answer:** The missing value is **2 cm²/cm³**. --- 1. **Problem Statement:** A cube stack has a Surface area ÷ Volume value of 1.2. Find the number of cubes used. 2. **Formula:** $$\frac{S}{V} = \frac{6}{n} = 1.2$$ 3. **Solve for $n$:** $$n = \frac{6}{1.2} = 5$$ 4. **Calculate number of cubes:** Number of cubes = $n^3 = 5^3 = 125$ 5. **Answer:** The cube stack uses **125 cubes**.