start by realising that angle b is 90°. Once you know this you can ad 90 and 55, getting 145. a tringle is 180° total so subtract 145 from 180 to get 35. 35 is one part of angle c. angle c is 90° so subtract 35 from 90 to get the missing part. this will get you 55°. now you have a triangle with the angles 80°, 55°, and x. once again, a triabgle is 180° total so add 80 and 55 then subtract that from 180. 80+55= 135. 180-135= 45. the answer is 45.
