Question

if m∠1 + m∠2 = 180°, and m∠2 = m∠4, then m∠1 + m∠4 = 180°. which reason justifies the statement? congruent supplements theorem definition of supplementary angles supplement theorem substitution property of equality

Explanation:

We know that $m\angle1 + m\angle2=180^{\circ}$ and $m\angle2 = m\angle4$. Since $m\angle2$ and $m\angle4$ are equal, we can replace $m\angle2$ with $m\angle4$ in the first - equation. This is the substitution property of equality which allows us to substitute equal quantities in an equation.

Answer:

Substitution Property of Equality