1. Unit 1-4 If and Then statements Conditional Statements in Geometry

2. Lets Begin—True or False (Truth Value ) 1. If today is July 4, then it is Independence Day. 2. If today is Independence Day, then it is July 4. 3. If today is not July 4, then it is not Independence Day. 4. If today is not Independence Day, then it is not July

3. More Truth Value 1. If today is Saturday, then it is a weekend day. 2. If today is a weekend day, then it is Saturday. 3. If today is not Saturday, then it is not a weekend day. 4. If today is not a weekend day, then it is not Saturday.

4. Building Understanding There are two parts to a conditional statement: Hypothesis Conclusion If two points lie on the same line, then they are collinear.

5. Identify the Hypothesis/Conclusion 1. If three points lie on the same plane, then the points are coplanar. 2. If a shape has 4 equal sides, then it is a square. 3. If a shape has 5 sides, then it is a pentagon. 4. If it is wet outside, then it must have rained.

6. Converse Statements To create a converse statement– Switch the hypothesis and the conclusion. If an angle measures 90 o, then it is a right angle.

7. Inverse Statements To create an inverse statement – Add the word not to both the hypothesis and conclusion. If an angle measures 90 o, then it is a right angle.

8. Contrapositive Statements To create a contrapositive statement – switch the hypothesis and conclusion and add the word not to both the hypothesis and conclusion. If an angle measures 90 o, then it is a right angle.

9. Bi-Conditional Statements To create an bi-conditional statement (use only if the conditional and converse are true)…..use if and only if to connect the two parts (remove the if and then) If an angle measures 90 o, then it is a right angle.

10. 1. If two angles are supplementary, then their measures add up to 180 o Converse

11. 1. If two angles are supplementary, then their measures add up to 180 o Inverse

12. 1. If two angles are supplementary, then their measures add up to 180 o contrapositive

13. 1. If two angles are supplementary, then their measures add up to 180 o Bi-conditional

14. 2. If a shape is a square, then it has 4 equal sides. Converse

15. 2. If a shape is a square, then it has 4 equal sides. Inverse

16. 2. If a shape is a square, then it has 4 equal sides. Contrapositive

17. 2. If a shape is a square, then it has 4 equal sides. Bi-Conditional