A | B |

acute triange (78) | A triangle whose largest angle measures less than 90°. |

angle (23) | The opening that is formed when two lines, line segments, or rays intersect. |

clockwise (75) | The same direction as the movement of a clock’s hands. |

congruent (66) | Having the same size and shape. |

counterclockwise (75) | The OPPOSITE direction as the movement of a clock’s hands. |

decagon (63) | A polygon with ten sides. |

flip (73) | Flipping a figure to produce a mirror image. |

full turn (75) | A turn measuring 360°. |

half turn (75) | A turn measuring 180°. |

hexagon (63) | A polygon with six sides. |

line of symmetry (79) | A line that divides a figure into two halves that are mirror images of each other |

obtuse triange (78) | A triangle whose largest angle measures more than 90° and less than 180°. |

octagon (63) | A polygon with eight sides. |

orientation (73) | Position of a figure. |

pentagon (63) | A polygon with five sides. |

polygon (63) | A closed, flat shape with straight sides. |

quadrilateral (63) | Any four-sided polygon. |

quarter turn (75) | A turn measuring 90°. |

reflection (73) | Flipping a figure to produce a mirror image. |

regular polygon (63) | A polygon in which all sides have equal lengths and all angles have equal measures. |

right angle (81) | An angle that forms a square corner and measures 90°. It is often marked with a small square. |

right triange (78) | A triangle whose largest angle measures 90°. |

rotation (73) | Turning a figure about a specified point called the center of rotation. |

similar (66) | Having the same shape but not necessarily the same size. |

straight angle (81) | An angle that measures 180° and thus forms a straight line. |

symmetry (79) | Correspondence in size and shape on either side of a dividing line, |

tessalation (82) | line. This type of symmetry is known as reflective symmet |

transformations (73) | The repeated use of shapes to fill a flat surface without gaps or |

translation (73) | Sliding a figure from one position to another without turning or flipping the figure. |

triangle (63) | A polygon with three sides and three angles. |

turn (73) | Rotation of a figure |

vertex (63) | (Plural: vertices ) A point of an angle, polygon, or solid where two or more lines, rays, or segments meet. |

isosceles triangle (78) | A triangle with at least two sides of equal length and two angles of equal measure. |

oblique (23) | Slanted or sloping; not horizontal or vertical. |

parallel lines (23) | Lines that stay the same distance apart; lines that do not cross. |

scalene triangle (78) | A triangle with three sides of different lengths. |

side (73) | A line segment that is part of a polygon. |

Vertical (23) | Upright; perpendicular to horizontal. |