1. What is the length of AB What is length of CD
Warm Up March 12, 2014 B
D, E, and F are midpoints. 10 8 D E 4
What is the length of AB
What is length of CD G 8 A C F

2. EOCT Week 9 #3

3. Conditional Statements
Also known as logic statements.
Types: Conditional, Inverse, Converse, & Contrapositive

4. a. Conditional Statements
Called if-then statements
Have 2 parts
Hypothesis- The part after if.
Conclusion- The part after then.
* Do not include if and then in the hypothesis and conclusion.

5. Hypothesis and Conclusion
Example:
If you are not satisfied for any reason, then return everything within 14 days for a full refund.

6. p: A figure is a rectangle. q: The diagonals are congruent.
A compound statement joined with an if…then.
CONDITIONAL
p: A figure is a rectangle.
q: The diagonals are congruent.
If p then q:
If a figure is a rectangle, then the diagonals are congruent.

7. Examples: Identify the Hypothesis and the conclusion.
1. If it is Saturday, then Beckham plays soccer.
Hypothesis-
Conclusion-
2. If points are collinear, then they lie on the same line.
it is Saturday
Beckham plays soccer
points are collinear
they lie on the same line

8. Negation
A statement can be altered by negation by writing the negative of the statement
Symbol: ~

9. b. Inverse
When you negate the hypothesis and conclusion of a conditional statement, you form the inverse.

10. Inverse
The inverse of a conditional statement is formed by negating both the hypothesis and the conclusion in the conditional
(Add “NOT”)
Conditional- If a figure is a triangle, then it has three angles.
Inverse- If a figure is not a triangle, then it does not have three angles.

11. p: A figure is a rectangle. q: The diagonals are congruent.
INVERSE
Negating a conditional.
p: A figure is a rectangle.
q: The diagonals are congruent.
If ~p then ~q:
If the figure is not a rectangle, then the diagonals are not congruent.

12. c. Converse
The converse of a conditional statement swaps the hypothesis and the conclusion.
Conditional- If a figure is a triangle, then it has three angles.
Converse- If a figure has three angles, then it is a triangle.

13. p: A figure is a rectangle. q: The diagonals are congruent.
Exchange the p and q of a conditional statement.
CONVERSE
p: A figure is a rectangle.
q: The diagonals are congruent.
If q then p:
If the diagonals are congruent, then the figure is a rectangle.

14. * Converses are not always true.
Conditional- If a figure is a square, then it has four sides.
Converse- If a figure has four sides, then it is a square.
* Not all four sided figures are squares. Rectangles also have four sides.

15. Counterexample Giving at least 1 example that disproves the statement.
Example: All prime numbers are odd.

16. d. Contrapositive
When you negate the hypothesis and conclusion of the converse of a conditional statement, you form the contrapositive.

17. (SWITCH the order and NEGATE)
Contrapositive
The contrapositive of a conditional statement is formed by switching and negating both the hypothesis and the conclusion.
(SWITCH the order and NEGATE)
Conditional- If a figure is a triangle, then it has three angles.
Contrapositive- If it does not have three angles, then a figure is not a triangle.

18. p: A figure is a rectangle. q: The diagonals are congruent.
Contrapositive
Negating the converse.
p: A figure is a rectangle.
q: The diagonals are congruent.
If ~q then ~p:
If the diagonals are not congruent, then the figure is not a rectangle.

19. Recap
Conditional: p → q Inverse: ~p → ~ q Converse: q → p Contrapositive: ~ q → ~ p

20. Truth Value
Decide whether the statement is true or false. If false, give a counterexample as to why it’s false. STMT: If you are a basketball player, then you are an athlete. Converse: Inverse: Contrapositive:
False, not all athletes play basketball. Could play baseball, golf, tennis, swim, etc.
False, even if you don’t play basketball, you can still be an athlete. Again, could play baseball, golf, tennis, swim, etc.
True

21. Give me some statements!!