Given: y || 2 Prove: m5+ m2+ m6 = 180°
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A
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1 1
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4
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6 7 z
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B

The relationships between angles formed by two parallel lines having a common a transversal include, alternate interior, vertically opposite, corresponding, alternate exterior, same side, interior and exterior

The correct option for the missing reason in step 3. is as follows;

Alternate interior angles are congruent

The reason the above option is correct is as follows:

The given parameters are;

Line y is parallel to line z

The figure ABC forms a triangle

The two column proof is presented as follows:

Statement                                            Reason

1. ABC is a triangle                              1. Given

2. lines y and z are parallel                2. Given

3. ∠1 is congruent to ∠5; ∠3 ≅ ∠6     3. Statement reason required

∠3 is congruent to ∠6

4. m∠1 = m∠5; m∠3 = m∠6                4. By definition of congruency

5. m∠1 + m∠2 + m∠3 = m∠LAM          5. By angle addition Postulate

6. m∠1 + m∠2 + m∠3 = 180°                6. Angles on a straight line

7. m∠5 + m∠2 + m∠6 = 180°               7. Substitution (property)

Required:

The reason for  the statement ∠1 ≅ ∠5; ∠3 ≅ ∠6

Solution:

From the attached diagram for the question, we have that angle ∠1 and angle ∠5 on line AC and ∠3 and ∠6 on line AB are alternate interior on two parallel lines, and they are therefore, congruent.

Therefore

∠1 ≅ ∠5, and ∠3 ≅ ∠6 by alternate interior angles theorem which states that alternate interior angles, which are the pair angles formed in the inside face of two parallel lines crossed by a common and the common transversal but on either of the transversal, are congruent

Therefore, the missing reason in Step 3 is;  Alternate interior angles are congruent

d

step-by-step explanation: