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All one has to do is realize that point E is a center of a circle going through points A, B, and C. This is obvious from the fact that ∠ A E B = 1 2 0 ∘ while ∠ A C B = 6 0 ∘ .
Then since A E = E C and ∠ A E C = 9 0 ∘ the ∠ E A C = 4 5 ∘ and ∠ B A C = 4 5 ∘ + 3 0 ∘ = 7 5 ∘