In △ABC, side BC is produced to point D.
Given: △ABC with exterior angle ∠ACD formed by producing BC to D.
To Prove: ∠ACD=∠CAB+∠ABC.
Answer the following:
(a) Write a complete paragraph proof of the exterior angle theorem stated above, clearly naming each axiom, postulate, or theorem that justifies every step.
(b) Using the theorem you have proved, calculate the magnitude of ∠ACD if ∠CAB=48∘ and ∠ABC=62∘.
(c) If ∠ACD is found to be a right angle, what can you conclude about the sum of ∠CAB and ∠ABC? Justify your answer briefly.