In a circle with centre O, chords AB and CD are equal while chord EF is longer than AB.
Use this information to answer the following questions.
a. (i) Prove that ∠AOB=∠COD.
b. (ii) Show that ∠EOF is greater than ∠AOB.
c. (iii) If ∠EOF=100∘, determine all possible values (in degrees) of ∠AOB and justify your answer.