## Elements of Geometry and Trigonometry |

### From inside the book

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**figures**. The method of enunciating them by the aid of particu- lar diagrams seems to have been adopted to avoid the difficulty which beginners experience in comprehend- ing abstract propositions . But in avoiding this diffi- culty ... Page 5

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**Figures**and the Measurement of Areas , - Problems relating to the Fourth Book , 41 57 68 98 BOOK V. Regular Polygons and the Measurement of the Circle , 109 BOOK VI . Planes and Solid Angles , 126 BOOK VII . Polyedrons , 142 BOOK VIII ... Page 10

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**figure**is a plane terminated on all sides by lines . B B 10 C A D If the lines are straight , the space they enclose is called a rectilineal**figure**, or polygon , and the lines themselves , taken together , form the contour , or ... Page 30

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**figure**has sides . E Let ABCDEFG be the proposed polygon . If from the vertex of any one angle A , diagonals B AC , AD , AE , AF , be drawn to the vertices of all the opposite angles , it is plain that the poly- gon will be divided into ... Page 31

... sides ( Prop . XXVI . ) ; that is , equal to twice as many right angles as the

... sides ( Prop . XXVI . ) ; that is , equal to twice as many right angles as the

**figure**has sides , wanting four right angles . Hence , the interior angles plus four right angles , is equal to twice as many right angles BOOK I. 31.### Other editions - View all

### Common terms and phrases

adjacent adjacent angles altitude angle ACB angle BAC ar.-comp base multiplied bisect Book centre chord circ circumference circumscribed common cone convex surface Cosine Cotang cylinder diagonal diameter dicular distance draw drawn equal angles equally distant equiangular equivalent figure formed four right angles frustum given angle given line gles greater homologous sides hypothenuse inscribed polygon intersection less Let ABC let fall logarithm measured by half number of sides oblique lines opposite parallelogram parallelopipedon pendicular perimeter perpen perpendicular plane MN polyedron polygon ABCDE prism proportional PROPOSITION pyramid quadrant quadrilateral quantities radii radius ratio rectangle regular polygon right angled triangle S-ABC Scholium secant secant line segment side BC similar sine solid angle solid described sphere spherical polygon spherical triangle square described straight line tang tangent THEOREM triangle ABC triangular prism vertex