The mean proportional of 64 and 4 is_____.

Options

A. 8
B. 32
C. 4
D. 16

Explanation

To find the mean proportional of 64 and 4, we can use the formula for mean proportional. The mean proportional \( B \) between two numbers \( A \) and \( C \) is defined such that:

\[ B^2 = A \times C \]

### Step-by-step Solution:

1. **Identify the values of A and C**:
- Here, \( A = 64 \) and \( C = 4 \).

2. **Apply the formula for mean proportional**:
- Substitute the values into the formula:
\[ B^2 = 64 \times 4 \]

3. **Calculate \( A \times C \)**:
- Perform the multiplication:
\[ B^2 = 256 \]

4. **Find the value of B**:
- To find \( B \), take the square root of both sides:
\[ B = \sqrt{256} \]

5. **Calculate the square root**:
- The square root of 256 is:
\[ B = 16 \]

6. **Conclusion**:
- Therefore, the mean proportional of 64 and 4 is:
\[ \text{Mean Proportional} = 16 \]

### Final Answer:
The mean proportional of 64 and 4 is **16**.