The reason that justifies why Rachel stated that m∠4 + m∠5 + m∠6 = 180° is: A. Triangle sum theorem
<h3>What is the Triangle Sum Theorem?</h3>
The triangle sum theorem states that for any given triangle, the sum of all its interior angles will be equal to 180°.
Thus, given the diagram showing a triangle, where ∠4, ∠5, and ∠6 are supplementary angles to the interior angles ∠1, ∠2, and ∠3 of the triangle.
Since all interior angles add up to 180°, the sum of their supplements, ∠4, ∠5, and ∠6 will also be 180°.
Therefore, the reason that justifies why Rachel stated that m∠4 + m∠5 + m∠6 = 180° is: A. Triangle sum theorem
Learn more about triangle sum theorem on:
brainly.com/question/19805547
