Question

This is confusing. can someone please help

Answer 1

For finding the measure of C you should know a line is 180° so 124°+C = 180 
now you can say: 
C = 180°- 124° = 56 ° 
so the answer is 56° :)))
i hope this is helpful 
have a nice day 

Answer 2

The answer is 56. 180-124=56.