If `4:5::7:x`, then the value of x will be

Options

A. `9.25`
B. `8.5`
C. `9.5`
D. `8.75`

Answer

To solve the proportion \(4:5::7:x\), we can set up the equation based on the property of ratios. This means that the ratio of 4 to 5 is equal to the ratio of 7 to \(x\).

### Step-by-Step Solution:

1. **Set Up the Proportion**:
\[ \frac{4}{5} = \frac{7}{x} \]

2. **Cross-Multiply**:
To eliminate the fractions, we can cross-multiply:
\[ 4 \cdot x = 5 \cdot 7 \]

3. **Calculate the Right Side**:
Calculate \(5 \cdot 7\):
\[ 5 \cdot 7 = 35 \]
So now we have:
\[ 4x = 35 \]

4. **Solve for \(x\)**:
Divide both sides by 4 to isolate \(x\):
\[ x = \frac{35}{4} \]

5. **Perform the Division**:
Now perform the division:
\[ x = 8.75 \]

Thus, the value of \(x\) is \(8.75\).

### Final Answer:
\[ x = 8.75 \]