A | B |

preimage | The original figure, before it has been transformed. |

dilation | A non-rigid transformation in which the preimage and image of a figure are similar. |

tessellation | A tiling of a plane with figures that leave no gaps or overlaps. |

image | The new figure which has been transformed using a motion-rule on each point of the preimage. |

map | A movement from the preimage to the image. |

transformation | The operation that maps the preimage onto the image. |

rigid | A transformation in which the preimage maps onto a congruent image. |

isometry | A rigid transformation that preserves length, angle measures, parallel lines, and distances between points. |

reflection | A rigid transformation that flips a figure over a given line. |

line of symmetry | A figure in a plane has a ______ if the figure can be mapped onto itself by a reflection in the line. |

rotation | A rigid transformation in which a figure is turned about a fixed point. |

rotational symmetry | A figure in a plane has _____ if the figure can be mapped onto itself by a rotation of 180 degrees or less. |

translation | A rigid transformation that slides a figure on a coordinate plane. The movement can be vertical, horizontal, or diagonal. |