## Helpful Links

## Theorem

## Conditional Statement

A statement of "if and then".

If it is sunny, then we are in Arizona.

"Hypothesis" "Conclusion"

Counterexample

An example proving the conditional statement wrong.

Summer time in California or other places in the world.

Converse

If we are in Arizona, then it is sunny.

## Inverse

If it is NOT sunny, then we are NOT in Arizona.

## Contrapositive

If we are NOT in Arizona, then it is NOT sunny.

## Postulates |
## Points, Lines, and Planes |

5 | Through any two points there exists exactly one line. |

6 | A line contains at least two points. |

7 | If two lines intersect, then their intersection is exactly one point. |

8 | Through any three non collinear points there exists exactly one plane. |

9 | A plane contains at least three non collinear points. |

10 | If two points lie in a plane, then the line containing them lies in the plane. |

11 | If two planes intersect, then their intersection is a line. |

## Math Instructor |