What is the formula to calculate resistance in a circuit?

The formula to calculate resistance in a circuit is derived from Ohm's Law, which states that voltage (V) equals current (I) multiplied by resistance (R). When rearranging this formula to solve for resistance, we get R = V/I. In the context of the choices provided, current (I) is represented by the letter A, leading to the formula R = V/A.

This formula shows that resistance is directly proportional to the voltage across a component and inversely proportional to the current flowing through it. Therefore, if the voltage increases while the current remains constant, resistance will increase, and conversely, if the current increases while voltage remains constant, resistance will decrease.

In this case, the other options present incorrect formulas that do not accurately reflect the relationship defined by Ohm's Law.