Answer:
Question #1
m∠4 + m∠7 = 180° - Given.
∠4 and ∠7 are supplementary angles - Definition of supplementary angles.
∠7 and ∠2 form a linear pair - Definition of linear pair.
∠7 and ∠2 are supplementary angles - Definition of linear pair.
m∠7 + m∠2 = 180° - Definition of supplementary angles.
m∠2 = m∠4 - Substitution property.
c ║ d - Converse of corresponding angles postulate.
Question #2
m∠3 = m∠8 - Given.
∠8 and ∠6 form a linear pair - Definition of linear pair.
∠8 and ∠6 are supplementary angles - Definition of linear pair.
m∠8 + m∠6 = 180° - Definition of supplementary angles.
∠3 and ∠6 are supplementary angles - Substitution property.
m∠3 + m∠6 = 180° - Definition of supplementary angles.
Question #3
p ║ q - Given.
∠1 ≅ ∠5 - Given.
∠1 ≅ ∠2 - Alternate interior angle theorem.
∠2 ≅ ∠5 - Substitution property.
~Hope this helps!~
