Prove the alternate segment theorem

Explanation:

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∠TAB = x°

∠TAC = 90°

(Angle between tangent and radius)

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∠CAB = a = 90 - x

∠CBA = 90°

(Angle in a semi circle)

∠ACB = 180 - 90 - a (3ʳᵈ angle of triangle)

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