Introduction to Proof

What is the first statement usually in a proof?

• What you want to prove

• The given

• A theorem

• A postulate

What is the last statement in a proof?

• The given

• What you are proving

• Vertical Angle Theorem

• Alt. Interior angle theorem

What are all valid reasons given in a proof?

• Alt. Interior angles are congruent.

• Vertical Angles are congruent.

• Reflexive Property

• Def. of Congruent Triangles

• Third Angles Theorem

What divides a segment into two congruent parts?

• An angle bisector

• A segment bisector

• Vertical Angles

• Alt. Interior Angles

What divides an angle into two congruent angles?

• Angle Bisector

• Segment Bisector

• Midpoint

• Vertical Angles

When you know all the sides and angles of one triangle are congruent to all the sides and angles of another triangle... you can say they are congruent by which of the following....

• Def. of Midpoint

• Def. of Segment Bisector

• Def. of Congurent Triangles

• Def. of Angle Bisector

What type of proofs did we address in class in our examples?

• paragraph proofs

• flow proofs

• two-column proofs

• Direct proofs

On a two column proof.. what do we write on the right side of the table?

• Statements

• Reasons

On a two column proof what do we write on the left side of the table?

• statements

• reasons

When giving reasons for angles to be congruent in a proof, which of the following may apply?

• Vertical angles congruent

• Alt. Interior angles are congruent

• Third angles theorem

• Corresponding Angles are Congruent

• None of these