Trimmer pot to fixed resistor conversion
simulate this circuit &ndash; Schematic created using CircuitLab

If the bottom part of the pot is 7.8K then the top should be 10K-7.8K = 2.2K. 

For the feedback voltage to equal the reference (2.495V), the voltage at the
top of the divider would have to be (10/7.8)*2.495V = 3.20V.