Question

If m∠A = m∠B and m∠A + m∠C = ∠D, then m∠B + m∠C = ∠D Which property is shown?

Answer 1

Answer:

Substitution Property

Step-by-step explanation:

So we know that:

$m\angle A=m\angle B$

And we also know that:

$m\angle A+m\angle C=\angle D$

And by using a specific property, we get that:

$m\angle B+m\angle C=\angle D$

Essentially, we substituted B for A.

So, this is an example of the substitution property, where if two sides/angles are congruent, we can substitute them for each other.