## Elements of Geometry and Trigonometry |

### From inside the book

Page 14

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**gles**ACE , ECD : therefore ACD + DCB is the sum of the three angles ACE , ECD , DCB : but the first of these three angles is a right angle , and the other two make up the right angle ECB ; hence , the sum of the two an-**gles**ACD and DCB ...Page 110

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**gles**at the centre must evidently be equal likewise ; and there- fore the value of each will be found by dividing four right an-**gles**by the number of sides of the polygon . Scholium 2. To inscribe a regu- lar polygon of a 110 GEOMETRY .Page 187

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**gles**AOB , AOC , COB , will be measured by AB , AC , BC , the sides of the spherical triangle . But each of the three plane an-**gles**forming a solid angle is less than the sum of the other two ( Book VI . Prop . XIX . ) ; hence any side ...### Contents

BOOK | 7 |

Problems relating to the First and Third Books 57 | 57 |

BOOK IV | 68 |

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### Common terms and phrases

adjacent adjacent angles altitude angle ACB angle BAC ar.-comp base multiplied bisect Book VII centre chord circ circumference circumscribed common cone consequently convex surface cosine Cotang cylinder diagonal diameter dicular distance divided draw drawn equally distant equations equivalent feet figure find the area formed four right angles frustum given angle given line gles greater homologous sides hypothenuse inscribed circle inscribed polygon intersection less Let ABC number of sides opposite parallelogram parallelopipedon pendicular perimeter perpen perpendicular plane MN polyedron polygon ABCDE PROBLEM Prop proportional PROPOSITION pyramid quadrant quadrilateral quantities radii radius ratio rectangle regular polygon right angled triangle S-ABC Scholium secant segment similar sine slant height solid angle solid described sphere spherical polygon spherical triangle square described straight line TABLE OF LOGARITHMIC tang tangent THEOREM triangle ABC triangular prism vertex