Final answer:
The question appears to pertain to Physics, focusing on electrical circuits and resistance, but the details are unclear without further context. To accurately determine the needed resistance value to equal 4 ohms, more information about the circuit configuration is necessary. Known circuit scenarios are provided for resistors in series and parallel with known voltages.
Step-by-step explanation:
The question asks about finding the value of resistance needed to make an equivalent resistance of 4 ohms. To properly address this question, more context is needed since the resistance could be part of a series circuit, a parallel circuit, or a combination of both. However, there's another part of the question mentioning circuits with four resistors.
We're presented with scenarios having four resistors with a total voltage of 17 V. In a series circuit, the voltage across each resistor is divided equally if the resistors have equal resistance, so each would get 17 V / 4. In a parallel circuit, the voltage across each resistor remains the same as the total voltage, so each would have 17 V across it. Additionally, when discussing the resistance of a wire stretched to four times its original length, we know from physics that resistance increases by the square of the factor by which the length is increased; hence, the resistance would increase by a factor of 16.