Neither do I. Can you provide more info?
A triangle always adds up to 180° so if you already have two angles, add them together and subtract them from 180° to find the missing angle.
I believe this depends solely on personal preference. A work of literature that you like may not be good to somebody else, so the way you feel about something makes it either good or bad. I believe I am pretty comfortable determining the quality of literature given that I have read a lot of books and have an overall grasp of each literary era throughout history. It can be easy to critique a text if you are knowledgeable enough about that particular era, style of writing, and general context, but it could also be quite difficult depending on the topic of that work.
