Question

from this given statement, select the definition, property, postulate, or theorem that justifies the prove statement. given: ∠1 is an exterior angle of △ced. prove: m∠1 = m∠3 + m∠4

Explanation:

The Exterior - Angle Theorem states that the measure of an exterior angle of a triangle is equal to the sum of the measures of the two non - adjacent interior angles. In \(\triangle CED\), \(\angle1\) is an exterior angle and \(\angle3\) and \(\angle4\) are the non - adjacent interior angles, so \(m\angle1=m\angle3 + m\angle4\).

Answer:

The Exterior - Angle Theorem