2.2 Types of Reasoning

IF 3...6...9...12...
AND 24...27...30...?
THEN the next term is going to be 33

• Inductive
• Deductive

All observed houses on South Street have roofs that are falling apart.  Sherry lives on South Street.  Her roof is falling apart. 

• Deductive
• Inductive

It is dangerous to drive on icy streets.  The streets are icy now so it is dangerous to drive now. 

• Deductive
• Inductive

All bears are mammals, all mammals have kidneys; therefore all bears have kidneys. 

• Deductive
• Inductive

If something is an angle, then it is acute. What is an appropriate counter-example?

• 70⁰

• 45⁰

• 120⁰

• True. There is no counterexample.

The Giants have lost their last seven games. Thus, they will probably lose their next game.

What type of reasoning was used?

• Inductive

• Deductive

All students go to school. You are a student. Therefore you go to school.

What type of reasoning was used?

• Inductive

• Deductive

Which is a counterexample to the following statement?

If an angle is obtuse, then it is $125\degree$ .

•  $90\degree$  

•  $57\degree$  

•  $160\degree$  

•  $180\degree$  

Which of the following provide a counterexample to the claim:

"If two angles are supplementary, then they are not congruent."

•  $40\degree\ and\ \ 140\degree$ 

•  $80\degree\ and\ \ 80\degree$ 

•  $30\degree\ and\ \ 150\degree$ 

•  $90\degree\ and\ \ 90\degree$ 

A counterexample is an example that proves a conjecture to be true.

• True

• False