If a transversal intersects two lines in such a way that a pair of consecuitive interior angles are supplementary; then two lines are parallel.

If a transversal intersects two parallel lines; then each pair of consecutive interior angles are supplementary.

If a Transversal intersects two lines in such a way that a pair of alternate interior angles are equal; then the two lines are parallel.

Theorem 6.3 : If a transversal intersects two lines such that a pair of alternate interior angles is equal, then the two lines are parallel.

Theorem 6.3 : If a transversal intersects two lines such that a pair of alternate interior angles is equal, then the two lines are parallel.

If a transversal intersects a pair of lines in such a way that a pair of alternate angles are equal, then two lines are ......... .

Theorem 6.5 : If a transversal intersects two lines such that a pair of interior angles on the same side of the transversal is supplementary, then the two lines are parallel.

Theorem 6.5 : If a transversal intersects two lines such that a pair of interior angles on the same side of the transversal is supplementary, then the two lines are parallel.

If a transversal intersects two parallel lines, then prove that each pair of alternate interior angles is equal.

If a transversal intersects two lines such that the bisectors of a pair of corresponding angles are parallel, then prove that the two lines are parallel.

If a transversal intersects two lines such that the bisectors of a pair of corresponding angles are parallel, then prove that the two lines are parallel.