Informal Geometry

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11/5/2009
Foundations basic logic, writing skills
Essential Question What are the elements of a
conditional statement? What is a converse? What
does conditional mean?
Homework If-then Comic Strip Analysis
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Keep a Lookout
Work out the problem independently as we will
take a class poll for the answer
Work out the problem independently then share
your work with your partner
Work together from the get-go
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Learning Goal 4 LOGIC

• Objective Recognize and analyze a conditional
  statements

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Conditional Statements

• Called if-then statements.
• Hypothesis- The part following if.
• Conclusion- The part following then.
• Do not include if and then in the hypothesis
  and conclusion.

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Hypothesis and Conclusion

• If it is sunny outside, then it is hot.

Truth Values?
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Kfed

• you give Kfed money
• he makes and awesome album

• If you give Kfed money, then he makes an
  awesome album.
• Hypothesis-
• Conclusion-

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• The converse of a conditional statement is formed
  by exchanging the hypothesis and the conclusion.
• Conditional- If it is sunny outside, then it is
  hot.
• Converse- If it is hot, then it is sunny outside.

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TRUTH VALUE?

• 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.
  Counterexample Rectangles also have four sides.

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Rewrite the statement as a conditional statement,
then find the converse.

• All teenagers are lazy.
• Conditional-
• Converse-

If you are a teen, then you are
lazt. If you are lazy, then you are a
teen.
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NO HOMEWORK FOR A MONTH!
NOT!

• When you negate (not) the hypothesis and the
  conclusion of a conditional statement, you form
  the inverse.

Example Cond. Stmt If is sunny outside, then
it is hot. Inverse If it is NOT sunny outside,
then it is NOT hot.
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When you negate the hypothesis and conclusion of
the converse of a conditional statement, you form
the contrapositive.
NOT!
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Example Cond. Stmt If it is sunny outside,
then it is hot. Converse If it is hot, then it
is sunny outside. ContrapositiveIf it is NOT
hot, then it is NOT sunny.
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Sum it up for us
Conditional statement Converse Inverse Contraposit
ive
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• Practice
• Conditional Statements worksheet

• QUIZ NEXT CLASS!!
• Cartoon Due Next Class