Which statement completes the proof that the sum of the angles of triangle prq is 180°? statement justification
angle 5 is congruent to angle pqr. alternate interior angles theorem
angle 1 is congruent to angle prq. alternate interior angles theorem
m∠1 + m∠rpq + m∠5 = 180° definition of a straight angle and
straight angle postulate
? substitution

The step missing is

, by substitution.

Step-by-step explanation:

We have

by Alternate Interior Angles Theorem.

, by Alternate Interior Angle Theorem.

, by Definition of a Straight Angle and a Straight Angle postulate.

, by substitution.

Now, remember that Alternate Interior Angles are those which are inside two parallels and different sides of the transversal line which intercept those parallels. Their theorem states that such angles are always congruent.

Then, the definition of a straight angle is that measures 180°, and its postulate is that adjacent angles on an straight angle must sum 180°, and they are supplementary.

for the points! : )

typically if you want , you would actually put questions here for us to you. but hey, that's just me. maybe someone will magically answer the questions for you without knowing what they are.