grade 10 · GEOM-005

Choose a valid proof reason

Select a precise justification for a step rather than relying on appearance.

Learn togetherFresh problem · seed 1944300357

Two parallel lines are cut by a transversal. Why are alternate interior angles congruent?

Let's work it out together.

Work through one checkpoint at a time. Your answer area opens after the reasoning.

Checkpoint 1

State exactly what is given in the diagram.
Checkpoint 2

Match the conclusion to a theorem whose hypotheses are satisfied.
Checkpoint 3

Reject reasons that concern a different geometric object or relationship.

Reflexive Property of Congruence.Triangle Sum Theorem.Alternate Interior Angles Theorem.Segment Addition Postulate.Definition of midpoint.