Lesson 6: geometry a unit 3: reasoning and proof

1. One way to show that a statement is not a good definition is to find a counterexample. A counterexample refers to an exception to the rule, if we deduct that exception is true, then the proposition is completely false. In this case, we have to find an exception to the definition, if the exception is true, then the definition is not true.

2. The option that show a true conditional is the fourth: If it's raining, then the humidity level is 100%. This shows the correct logical conditional, other options are not logical. In this case, the hypothesis is "if it's raining", and the conclusion is "the humidity is 100%". This is the right order, because humidity derive from raining, not the opposite.