Final answer:
The student's question concerns proving an equality between an exterior angle of a triangle and the sum of two interior, non-adjacent angles, relying on the properties of angles in triangles and the exterior angle theorem.
Step-by-step explanation:
The question deals with geometric principles, specifically the properties of angles within a triangle and the exterior angles. In a triangle, the sum of the interior angles is always equal to 180 degrees. When an exterior angle is formed by extending one of the sides of a triangle, it is equal to the sum of the two non-adjacent interior angles. This is known as the exterior angle theorem.
The problem involves proving that m∠ZAB = m∠ACB + m∠CBA, which is based on the understanding that m∠ZAB + m∠CAB = 180° and m∠CAB + m∠ACB + m∠CBA = 180°. By substituting and simplifying, we can prove the required equality.