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# Geometry

### Angles & Triangles

Question | Answer |
---|---|

Angle | When two lines meet at a point (Vertex) |

Vertex | The point where the two arms of an angle meet |

Protractor | The device for measuring angles |

Degrees' | The unit used to measure angles |

Constructing Angles | Drawing an angle accurately with a protractor |

Acute Angle | An Acute angle is greater than zero', but less than 90' |

Right Angle | A Right Angle is exactly 90' |

Obtuse Angle | An Obtuse Angle is greater than 90' but less than 180' |

Straight Angle | A Straight Angle is exactly 180' |

Reflex Angle | A Reflex Angle is greater than180' but less than 360' |

A Revolution or Perigon | A Revolution or Perigon is an angle of 360' A full circle |

Complementary Angles | Complementary Angles are 2 or more angles that add up to 90' |

Supplementary Angles | Supplementary Angles are 2 or more angles that add up to 180' |

< symbol | The < symbol is saying "the angle of" |

Writing the angle name, we use < and _________ _________ letters | Three Capital letters |

The three angles in any Triangle added up to ________ | 180' |

The three triangle according to their sides are called | Equilateral, Isosceles and Scalene Triangles |

An Equilateral Triangle has | All sides equal in length All angles equal 60' |

An Isosceles Triangle has | Two sides of equal length Opposite angles are equal |

A Scalene Triangle has | No equal sides No equal angles |

The three Triangles according to their angles are called | Right- angled triangle, Acute- angled triangle and an Obtuse- angled triangle |

A Right -angled triangle | Has ONE angle that equals 90' |

An Acute-angled triangle | Has ALL angles smaller than 90' |

An Obtuse-angled triangle | Has ONE angle GREATER than 90' ( less than 180') |

Interior Angle refers to | Refers to the angles inside the triangle |

Exterior Angles refers to | Refers to the angle outside the triangle |