Presentation on theme: "Proofs & Perpendicular Lines Sec. 3.2 p. 136 GOALS: To learn the characteristics of three different types of proofs To write a paragraph proof To learn."— Presentation transcript:
Proofs & Perpendicular Lines Sec. 3.2 p. 136 GOALS: To learn the characteristics of three different types of proofs To write a paragraph proof To learn theorems on perpendicular lines
Theorems 3.1 & 3.2 Theorem 3.1 g h 2 1 Theorem 3.2
Theorem 3.3 If two lines are perpendicular, then they intersect to form four right angles. l m
Examples Which theorem or postulate justifies the following given that the lines are perpendicular? 5 6 2) 1) l m 4 3
Two-Column Proof of Theorem 3.2 Given: Prove: Statements Reasons 1 2 B A C
Three types of Proofs & Characteristics 1.Two column proof: Most formal Lists numbered statements in left column and a reason for each statement in the right column 2.Paragraph proof: Describes the logical argument with sentences More conversational 3.Flow proof: Uses the same statements and reasons as a two- column proof, but the logical flow connecting the statements is indicated by arrows
See notes sheet for an example of the three types of proofs!