Name Date: Period

Mod 4.3

Proving Lines are Parallel

TERM: DEFINITION:

Conditional Statement A statement written in

NOTATION:

format.

Hypothesis The phrase following but NOT INCLUDING the word

Conclusion The phrase following but NOT INCLUDING the word -Hoe-yl

Converse The statement formed by exchanging the

and COPI of a

conditional statement.

Same-Side Interior Angles Postulate

Conditional Statement-lf two parallel lines are cut by a transversal, then the pairs of same-side interior angles are

supplementary.

Converse-lf two lines are cut by a transversal so that a pair of same-side interior angles are supplementary,

then the lines are parallel.

Alternate Interior Angles Theorem

Conditional Statement-lf two parallel lines are cut by a transversal, then the pairs of alternate interior angles

have the same measure

Converse-if two lines are cut by a transversal so that any pair of alternate interior angles are congruent, then

the lines are parallel.

Corresponding Angles Theorem

Conditional Statement- If two parallel lines are cut by a transversal, then the pairs of corresponding angles have the

same measure.

Converse-lf two lines are cut by a transversal so that any pair of corresponding angles are congruent, then the

lines are parallel.