## Elementary Geometry PlaneExcerpt from Elementary Geometry Plane This text-book aims to carry out the spirit of the admirable suggestions made by the Committee on Secondary School studies, appointed by the National Educational Association. While the book speaks for itself, some of its leading features may here be pointed out. (1) It aims at a combination of Euclidean rigor with modern methods of presentation suitable for beginners in the study of demonstrative geometry; but the rigor is not regarded as consisting so much in excessive formality of expression as in soundness of structural development. (2) It regards the postulates as a body of fundamental conventions that constitute a definition of Euclidean space, from which (with the definitions of particular figures) other properties of such space are to be unfolded by a series of logical steps. (3) It regards the postulates of construction as determining or defining the province of elementary as distinguished from higher geometry. Accordingly no hypothetical figure is made the basis of an argument until its construction has been proved to be reducible to the construction postulates; and thus problems, no less than theorems, have their place in the logical development of the subject. (4) The theorems and problems are arranged in natural groups and subgroups with reference to their underlying principle, thus exhibiting the gradual unfolding of the space relations. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works. |

### What people are saying - Write a review

Reviews aren't verified, but Google checks for and removes fake content when it's identified

User Review - Flag as inappropriate

you could make it better if you should a videoof it in action

### Contents

Angles | 7 |

Regular polygons | 17 |

Pyramidsthe Tetrahedron | 26 |

Parallels and perpendiculars | 35 |

Note | 39 |

Cube cuboid prism wedge | 42 |

Heights and distances | 48 |

Points lines surfaces solids | 55 |

CONSTRUCTIONS | 103 |

MISCELLANEOUS EXERCISES | 115 |

If two angles of a triangle are unequal | 122 |

third side has the greater included angle | 128 |

a The straight line drawn through | 141 |

The locus of a point which is equidistant | 147 |

MISCELLANEOUS EXERCISES | 154 |

AREA OF PARALLELOGRAM | 167 |

THEORETICAL GEOMETRY | 63 |

If the sum of two adjacent angles is equal | 67 |

then the two straight lines are parallel | 71 |

Straight lines which are parallel to the same | 77 |

ANGLES OF A TRIANGLE A POLYGON | 80 |

If two angles of a triangle are equal | 96 |

AREA OF POLYGON | 178 |

If a triangle and a parallelogram stand | 185 |

MISCELLANEOUS EXERCISES ON AREA | 186 |

ILLUSTRATIONS | 201 |

Projections | 210 |

### Other editions - View all

### Common terms and phrases

acute base bearing bisector bisects called centre circle congruent Construct contained converse copy corners corresponding Data describe diagonals distance divided Draw Draw a straight drawn edge ends equal equal sides equidistant equilateral triangle equivalent exterior angles falls feet figure find a point Find the area folding formed four given given straight line greater half height inches intersect isosceles triangle length locus mark means Measure meet method mid-point miles moves observed opposite sides pair parallel parallelogram perpendicular polygon position possible produced prove quadrilateral ABCD radius rectangle regular Repeat Ex respectively rhombus right angles right-angled triangle round ship Show square straight line surface symmetry Take THEOREM triangle ABC units vertex vertices yards

### Popular passages

Page xiv - If there are three or more parallel straight lines, and the intercepts made by them on any straight line that cuts them are equal, then the corresponding intercepts on any other straight line that cuts them are also equal.