Find 'X' if the below three numbers are in proportion.
2.6,1.3,X

Options

A. 1.95
B. 1.83
C. 3.9
D. 0.65

Answer

To find the value of 'X' when the numbers 2.6, 1.3, and X are in proportion, we can use the property of proportions.

### Step-by-Step Solution:

1. **Understanding Proportions**:
When three numbers a, b, and c are in proportion, it means that the ratio of the first number to the second number is equal to the ratio of the second number to the third number. This can be expressed as:
\[ \frac{a}{b} = \frac{b}{c} \]
In our case, we have:
\[ \frac{2.6}{1.3} = \frac{1.3}{X} \]

2. **Cross-Multiplying**:
To eliminate the fractions, we can cross-multiply:
\[ 2.6 \cdot X = 1.3 \cdot 1.3 \]

3. **Calculating the Right Side**:
Calculate \(1.3 \cdot 1.3\):
\[ 1.3 \cdot 1.3 = 1.69 \]
So, we have:
\[ 2.6 \cdot X = 1.69 \]

4. **Solving for X**:
Now, divide both sides by 2.6 to isolate X:
\[ X = \frac{1.69}{2.6} \]

5. **Performing the Division**:
Now, calculate \( \frac{1.69}{2.6} \):
\[ X = 0.65 \]

6. **Conclusion**:
Therefore, the value of X is:
\[ X = 0.65 \]