Last Night’s Homework: 2.2 Handout Tonight’s Homework: 2.3 Handout WELCOME 2.3: Proofs Last Night’s Homework: 2.2 Handout Tonight’s Homework: 2.3 Handout QUIZ BLOCK DAY!

 

Chapter 2 Section 3

Multiplication Property Division Property Addition Property Subtraction Property Multiplication Property Division Property If a=b & c≠0, then a÷c = b÷c If a=b, then a+c = b+c If a=b, then a-c = b-c If a=b, then ac = bc Reflexive Property Symmetric Property Transitive Property Substitution Property If a=b, then a & b can be switched For any # a, a = a If a=b, then b=a If a=b & b=c, then a = c

Two Column Proofs Allow us to organize arguments using numbering to connect statements with valid reasoning. Statements Reasons

Two Column Proofs   Statements Reasons

≅ Complement Theorem: If two ∠s are complements of the same ∠ or of congruent ∠s, then the ∠ s are ≅.

Right Angle ≅ Theorem: All right angles are ≅ Vertical Angle Theorem: Vertical angles are ≅.

Biconditional Statements If and Only If Form (iff): A statement using the form “Hypothesis if and only if Conclusion.” (Abrev. iff) Example: It’s a right angle iff the angle has a measure of 90° Essentially a conditional and converse written at same time, must be true “forward” and “backward.” Conditional: If it’s a right angle then the angle has a measure of 90° Converse: If the angle has a measure of 90° then it’s a right angle.