The formula to calculate the unknown resistor \( R_x \) in a balanced Wheatstone bridge is:
\[ R_x = \frac{R_2 \cdot R_3}{R_1} \]
Let's assume the following values:
Step 1: Apply the formula:
\[ R_x = \frac{R_2 \cdot R_3}{R_1} = \frac{20 \cdot 2}{10} = 4 \text{k}\Omega \]
Step 2: The value of the unknown resistor \( R_x \) is 4 kΩ.