By the definition of a parallelogram, AB∥DC. AD is a transversal between these sides, so ∠A and ∠D are angles. Because AB and DC are , the same-side interior angles must be by the same-side interior a:
same-side interior
By the definition of a parallelogram, AB∥DC. AD is a transversal between these sides, so ∠A and ∠D are angles. Because AB and DC are , the same-side interior angles must be by the same-side interior a:
parallel
By the definition of a parallelogram, AB∥DC. AD is a transversal between these sides, so ∠A and ∠D are angles. Because AB and DC are , the same-side interior angles must be by the same-side interior a: