STANDARD G.CO.C.9
Prove theorems about lines and angles. *Theorems include: vertical angles
are congruent; when a transversal crosses parallel lines, alternate interior
angles are congruent and corresponding angles are congruent; points on a
perpendicular bisector of a line segment are exactly those equidistant from
the segment’s endpoints.* |

WORKSHEETS |
Regents-Lines and Angles 1
GEO |
6 |
TST
PDF
DOC
TNS |

Regents-Lines and Angles 2
GE |
14 |
TST
PDF
DOC
TNS |

Regents-Lines and Angles 3
A |
6 |
TST
PDF
DOC
TNS |

Regents-Line and Angle Proofs
GE |
3 |
TST
PDF
DOC
TNS |

Practice-Lines and Angles 1 |
5 |
WS
PDF |

Practice-Lines and Angles 2 |
10 |
WS
PDF |

Practice-Lines and Angles 3 |
10 |
WS
PDF |

Practice-Lines and Angles 4 |
20 |
WS
PDF |

Practice-Lines and Angles 5 |
6 |
WS
PDF |

Practice-Line and Angle Proofs |
6 |
WS
PDF |

RELATED TOPICS |

Negations
GE |
10 |
TST
PDF
DOC
TNS |

Compound Statements
GE/A |
6/21 |
TST
PDF
DOC
TNS |

Inverse, Converse, Contrapositive and
Conditional Statements 1a
GE/A
*MC* |
12/28 |
TST
PDF
DOC
TNS |

Inverse, Converse, Contrapositive and
Conditional Statements 1b
GE/A
*bimodal* |
TST
PDF
DOC |

Regents-Indirect Proof
B |
5 |
TST
PDF
DOC
TNS |

Practice-Statements |
10 |
WS
PDF |

Practice-Compound Statements 1 |
6 |
WS
PDF |

Practice-Compound Statements 2 |
9 |
WS
PDF |

Practice-Compound Statements 3 |
10 |
WS
PDF |

Practice-Compound Statements 4 |
6 |
WS
PDF |

Practice-Inverse |
5 |
WS
PDF |

Practice-Converse |
10 |
WS
PDF |

Practice-Contrapositive |
6 |
WS
PDF |

Practice-Indirect Proof |
5 |
WS
PDF |

Practice-Mathematical Induction |
4 |
WS
PDF |

VIDEOS |
Identifying collinear points |
VID |

Naming lines, segments, and rays |
VID |

Identifying parallel or skew lines |

Relating parallel and perpendicular lines |
VID |

Classifying angles |
VID |

Identifying angle pairs |
VID |

Using the Vertical Angles Theorem |
VID |

Using the Congruent Supplements
Theorem |

Using the segment addition postulate |
VID |

Using the angle addition postulate |
VID |

Writing biconditionals |
VID |

Separating a biconditional into parts |

Writing a definition as a biconditional |

Recognizing good definitions |

Using inductive reasoning |
VID |

Finding a counterexample |

Using the Law of Detachment |
VID |

Using the Law of Syllogism |

Writing a conditional statement |
VID |

Finding a counterexample to a
conditional statement |

Using converses of conditional statements |
VID |

Using converses of conditional statements |
VID |

Writing biconditionals |
VID |

Separating a biconditional into parts |

Writing a definition as a biconditional |

Recognizing good definitions |

Using indirect proof |
VID |