Ok the angle you see there is a right angle because it has a box, meaning that angle is 90 degrees. The tip angle is 23 degrees. Add 90+23 to get 113 and then subtract by 180 to get 67, so angle c is 67 degrees.
if you are looking for the angles measurement you have 23 so then you need to figure out the other angles subtract 23 from 180 then you need to divide your answer but c is going to be less the the other side ill call a so a will be larger then c
