Circle theorem exam question

2017 ECZ paper 1

[sundaymuchika]

One thing I like, you make things thanks for the video Sir

[marriamgato]

But why are you not dividing the answer 110 degrees by 2

[takupasu]

sir i know all concept of circle theorem, but when i see this question, my brain blank, i can;t remember what i study, what should i do?