Answer: The measurement is 65 degrees.
Step-by-step explanation: The DAC line is 180 degrees. With angle BAD known, BAC could be figured out using the supplementary angle rule. For this, angle of BAC= 180 degrees minus 123 degrees (which is BAD) which become 57 degrees. Now with BAC solved, the triangl’s degree measurement would be easy. The triangle’s angles add up to 180 degrees (number of sides * 60 degrees to get total degree). So 180-58-57=65 degrees which is angle C.