Answer:
9 1/3
Step-by-step explanation:
4 2/3 = 14/3
14/3/1/2
14/3 x 2/1
28/3= 9 1/3
If two angles are equal, then they are both obtuse
I'll assume those are squares. We know D is an identity:

Dividing through by


That's A.
Dividing the original through by


Not quite B, wrong sign on tangent.
C has the wrong sign on cosine squared as well.
Identities: A & D