Given: OO with central angles ZAOC ZBOD Prove: AC BD A C Complete the missing parts of the paragraph proof. Proof: We know that central angles are B D congruent, because it is given. We can say that segments AO, CO, BO, and DO are congruent because Then by the congruency theorem, we know that triangle AOC is congruent to triangle BOD. Finally, we can conclude that chord AC is congruent to chord BD because