(a) One point in common
∠COD and Z AOD have point O m common
Two Points in common
(b) Two points in common
∠AOB and ∠BOC have point O and B in common
(c) Three points in common
∠AOB and ∠BOC have points O, E, B in common
(d) Four points in common
∠BOA and ∠COA have points O, E, D, A in common
(e) One ray in common
Ray (\vec{OC}) is common between ∠BOC and ∠AOC.
