What must be added together to find the total resistance in a series circuit?

To find the total resistance in a series circuit, you add the resistance values of each component or load connected in series. In a series circuit, the current has only one path to follow, so the total resistance is simply the sum of the individual resistances. This method reflects how the entire circuit impedes electrical flow; as more resistances are added, it becomes more difficult for current to traverse the circuit, leading to an increase in total resistance.

The other options do not accurately describe how to calculate total resistance in a series circuit. Adding the inverses would pertain to calculating total resistance in a parallel circuit. Calculating the average of the resistances or using the square root is not relevant in this context and does not correspond to the correct approach for determining total resistance in a simple series arrangement. Therefore, the principle of summation for resistances in series is what makes it the correct answer.