Chapter E, Problem 2.7EX

To determine

To Find:

The property.

Answer to Problem 2.7EX

The statement is justified by the property option (b) Substitution.

Explanation of Solution

Given information:

If $m\angle A=m\angle B$ and $m\angle D=m\angle A+m\angle C$ .

If $m\angle A=m\angle B$ and $m\angle D=m\angle A+m\angle C$ .

Then

  $m\angle D=m\angle B+m\angle C$ can be justified simply by substitution method.

Therefore, the statement is justified by the property option (b) Substitution.