## Elements of Geometry |

### From inside the book

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Page 126

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**pyramid**is a solid formed by several**triangular**planes proceeding from the same point and terminating in the sides of Fig . 196. a polygon ABCDE ( fig . 196 ) . Fig . 202 . The polygon ABCDE is called the base of the**pyramid**, the point ... Page 127

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**triangular pyramids**, which have for their common base the above triangle ; and these several pyramids will determine the positions of the several solid angles of the polyedron with respect to the base . This being supposed ; Two ... Page 142

... pyramids that have a common vertex , and whose altitudes are the same , or whose bases are situated in the same ...

... pyramids that have a common vertex , and whose altitudes are the same , or whose bases are situated in the same ...

**triangular pyramid**, of which S is the vertex and ABC the base ; if the sides SA , SB , SC , AB , AC , BC , be bisected ... Page 143

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**triangular**prism EGI - CFH will be half of this parallelopiped ( 397 ) ; on the other hand , the prism AGH - FDE is ...**pyramids**S - DEF , E - GBI ; now we say that these two**pyramids**are equal to each other . Indeed , since the ... Page 144

... pyramids S - DEF , E - GBI , is less than the prism AGH - FDE ; therefore the pyramid S - ABC , which is composed of ...

... pyramids S - DEF , E - GBI , is less than the prism AGH - FDE ; therefore the pyramid S - ABC , which is composed of ...

**triangular pyramid**is less than half of the product of its base by its altitude . - = Fig . 215 . THEOREM . 413. The ...### Other editions - View all

### Common terms and phrases

ABC fig adjacent angles altitude angle ACB angle BAC base ABCD bisect centre chord circ circular sector circumference circumscribed common cone consequently construction convex surface Corollary cube cylinder Demonstration diagonals diameter draw drawn equal angles equiangular equilateral equivalent faces figure formed four right angles frustum GEOM given point gles greater hence homologous sides hypothenuse inclination intersection isosceles triangle JOHN CRERAR LIBRARY join less Let ABC let fall line AC mean proportional measure the half meet multiplied number of sides oblique lines opposite parallelogram parallelopiped perimeter perpendicular plane MN polyedron prism produced proposition radii radius ratio rectangle regular polygon right angles Scholium sector segment semicircle semicircumference side BC similar solid angle sphere spherical polygons spherical triangle square described straight line tangent THEOREM three angles triangle ABC triangular prism triangular pyramids vertex vertices whence