## Elements of Geometry |

### From inside the book

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Page vii

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**perimeter**. The first section of the second part contains the properties of planes and of solid angles . This part is very necessary for the understanding of solids , and of figures in which different planes are considered . We have ... Page 2

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**perimeter**of the polygon . 14. The polygon of three sides is the most simple of these figures , and is called a triangle ; that of four sides is called a quadrilateral ; that of five sides , a pentagon ; that of six , a hexa- gon , & c ... Page 17

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**perimeter**in more than two points . THEOREM . 69. If two straight lines AB , CD ( fig . 36 ) , are perpendicular Fig 36 . to a third FG , these two lines will be parallel , that is , they will not meet if produced ever so far ... Page 66

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**perimeters**of similar polygons are as their homolo- gous sides , and their surfaces are as the squares of these sides ...**perimeter**of the second figure , as one antecedent , is to its consequent ( Iv ) , or as the side AB is to its ... Page 69

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**perimeter**multiplied by half of the radius of the inscribed circle . For the triangles AOB , BOC , AOC ( fig . 87 ) , which have Fig . 87 . their common vertex in O , have for their common altitude the radius of the inscribed circle ...### 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