3Theorem 3.3Theorem 3.3If two lines are perpendicular, then they intersect to form four right angles.ml
4ExamplesWhich theorem or postulate justifies the following given that the lines are perpendicular?1)65m2)34l
5Two-Column Proof of Theorem 3.2 AGiven:Prove:21BCStatements Reasons
6Three types of Proofs & Characteristics Two column proof:Most formalLists numbered statements in left column and a reason for each statement in the right columnParagraph proof:Describes the logical argument with sentencesMore conversationalFlow proof:Uses the same statements and reasons as a two-column proof, but the logical flow connecting the statements is indicated by arrows
7See notes sheet for an example of the three types of proofs!