The missing parts are
Arc AC is 175 degrees
length of arc AC is 18.33 units
How to find angle AC
Angle AC is solved using the knowledge of angles in a circle
Assuming, arc AC = arc ADC, that is the minor arc
arc AC = 360 - angle ABC
arc AC = 360 - 185
arc AC = 175 degrees
length of arc AC = theta / 360 * 2 * π * r
where:
theta = angle ADC = 175 (intercepted arc AC is equal to central angle)
r = 6
length of arc AC = 175/360 * 2 * π * 6
length of arc AC = 18.33 units