Complete the proportion: 6 : 8 = 4 :

Solution:
1. Given proportion:
- 6 : 8 = 4 : x

2. Proportions mean the ratios are equal:
\frac{6}{8} = \frac{4}{x}

3. Cross-multiply to solve for x:
- 6 \cdot x = 8 \cdot 4

4. Calculate the right side:
- 8 \cdot 4 = 32

5. Solve for x:
- 6x = 32
- Divide both sides by 6: x = \frac{32}{6}

6. Simplify the fraction:
- x = \frac{16}{3}

Answer: The value of x that completes the proportion is \frac{16}{3}.