1. 1 Conditional Statements “IF-THEN”

2. If- Then Statements If- Then Statements are commonly used in everyday life. Advertisement might say: “If you buy our product, then you will be happy". Notice that “If-Then” statements have two parts, a hypothesis(the part following “if”) and a conclusion(the part following “Then”)

3. What is Conditional Statement? Conditional Statements = “If-Then” statements. The IF-statement is the hypothesis and the THEN-statement is the conclusion. 3

4. Identify Hypothesis and Conclusion. If a polygon has 6 sides, then it is a hexagon. Hypothesis: A polygon has 6 sides Conclusion: It is a hexagon. 4

5. Identify Hypothesis and Conclusion John will advance to the next level of play if he completes the maze in his computer game. Hypothesis: John completes the maze in his computer game Conclusion: He will advance to the next level of play 5

6. Write a Statement in If-Then Form A five-sided polygon is a pentagon Hypothesis: A polygon has five sides Conclusion: It is a pentagon If a polygon has five sides, then it is a pentagon 6

7. True or False? “IF-THEN“ statements can be TRUE or FALSE. Its false when the hypothesis is true and the conclusion is false. EX: If you live in Idaho, you live in Boise False EX: Not all people who live in Idaho live in Boise

8. 8 True or False? EX: If two angles are congruent, then they are vertical Make sure to show an example to prove false. EX: False, We can have two congruent angles that are not vertical 8

9. Abbreviation Form of statement: If hypothesis then conclusion We say : p  q, where p is called hypothesis, q is called conclusion 9

10. Some More… New Statements can be formed from the original statement. Original “If-Then”: p  q Converse: q  p Inverse: ~ p  ~ q, where “~” means NOT Countrapositive: ~ q  ~ p

11. Examples: Rewrite the following statements in “If-Then” form. Than write a converse, inverse and contrapositive. Ex: “All elephants are mammals” If-Then form: If an animal is an elephant, then it is a mammal Converse: If an animal is a mammal, then it is an elephant Inverse: If an animal is not an elephant, then it is not a mammal Countrapositive: If an animal is not a mammal, then it is not an elephant