Intro: Two Column Proofs

Which card can you use to get to step 3?

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Which card can you use to get to step 3?

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Which card can you use after step 2?

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Which card can you use after step 2?

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Give the Reason for #1.

• Given

• Segment Addition Property

• Addition Property of Equality

• PQ + QR = PR

• Transitive Property of Equality

Use Law of Syllogism to make a conclusion.
If the perimeter of a square is 20 ft, then the length of a side is 5 ft.
If the length of a side of a square is 5 ft, then the area is 25 ft².

• If the side of a square is 5 ft, then the perimeter is 20 ft.
• If the perimeter of a square is 20 ft, then the area is 25 ft²
• If the area of a square is 25 ft², then the side length is 5 ft. 
• If the are of a square is 25 ft², then the perimeter is 20 ft.

Which law of logic is this?

If I clean the bathroom, then I don't have to do the dishes.

I cleaned the bathroom.

Therefore, I don't have to do the dishes.

• Law of Detachment

• Law of Syllogism

• Law of Contrapositive

• None

Which law of logic is this:
If my mom stays home, then she won't buy shoes.
If she doesn't buy shoes, then she'll wear an old pair. 
Therefore if my mom stays home, then she will wear an old pair of shoes.

• Contrapositive
• Converse
• Detachmant
• Syllogism

p→q
q→r
∴p→r
Which law is modeled?

• Law of Syllogism
• Law of Detachment
• Law of Contrapositive
• Law of Shannon

p→q
p
∴q
Which law is modeled?

• Law of Syllogism
• Law of Detachment
• Law of Contrapositive
• Law of Shannon