R = 2.09K ± 80 Ohms
The current flowing in Figure 1 is 9V/3R.
The Voltage across R3 is
V = R*I = R*9/3R = 3V
Lab 2 Exercise
Table 1 contains measured values of the current through a resistor as a function of the voltage across the resistor.
Figure 1   A voltage divider circuit is shown.