Hi There!
The answers you have stated in the picture look correct to me.
The reason I say that is because the 2nd and 3rd boxes are just asking if from corner to coner or the same length and they are. The reason the first one is correct is because the other corner is (0,0) and the other 2 corners have (a,b) which makes C (a,b).
Good Job :)
Hope This Helps!
