How do you find the missing Resistor in a series?

To find the missing resistor in a series circuit, first calculate the total resistance using the formula ( R_{total} = R_1 + R_2 + R_3 + ... + R_n ), where ( R_1, R_2, R_3, ) etc., are the known resistors. Rearrange the equation to solve for the missing resistor ( R_x ) as ( R_x = R_{total} - (R_1 + R_2 + ... + R_n) ). If you know the total voltage and current in the series, you can also use Ohm’s Law (( V = I \times R )) to find the total resistance and then determine the missing resistor.