1. **Problem:** The volume of the prism is 2,688 cubic units. Find the missing side $x$ given the sides 8 units, 10 units, and 12 units. 2. **Formula:** Volume of a prism = Base Area $\times$ Height. 3. Since the base is a parallelogram, Base Area = base $\times$ height. Here, the base sides are 8 and 10 units, and the height is 12 units. 4. Let the missing side $x$ be the height of the parallelogram base corresponding to side 10 units. 5. Volume = Base Area $\times$ prism height = $2,688$. 6. Base Area = $10 \times x$ (since base side is 10 units and height is $x$). 7. Prism height = 12 units. 8. So, $2,688 = 10 \times x \times 12$. 9. Simplify: $$2,688 = 120x$$ 10. Divide both sides by 120: $$\frac{2,688}{\cancel{120}} = \frac{120x}{\cancel{120}}$$ 11. Calculate: $$22.4 = x$$ 12. **Answer:** The missing side $x$ is 22.4 units.