The Elements of Solid Geometry |
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Common terms and phrases
altitude axis bisect centre circle circular section circumcentre circumference circumscribed spheres common section concurrent lines cube diagonals diameter dicular dihedral angle draw drawn perpendicular equal and parallel equidistant Find the locus find the radius Find the volume fixed point frustum given plane inscribed joining the middle lateral surface line joining lune middle points non-planar lines number of sides octahedron opposite edges pair of opposite parallel planes parallel straight lines parallel to CD parallelepiped parallelogram perpen perpendicular to BC plane ABC plane angles plane BOC plane parallel plane passing plane perpendicular polygon PQR polyhedra polyhedron PQQ'P PROP prove radii rectangle regular hexagon regular polygon regular tetrahedron revolves right circular cone right circular cylinder solid angle spherical angle spherical polygon spherical triangle square tangent-plane three planes traces triangle ABC triangular prism triangular pyramid trihedral vertex
Popular passages
Page 82 - A Cone is a solid figure, described by the revolution of a right.angled triangle about one of the sides containing the right angle, which side remains fixed.
Page 77 - A cylinder is conceived to be generated by the revolution of a rectangle about one of its sides as an axis.
Page 118 - The area of a lune is to the surface of the sphere as the angle of the lune is to four right angles, or as the arc which measures that angle is to the circumference.
Page 116 - The sum of the angles of a spherical triangle is greater than two and less than six right angles ; that is, greater than 180° and less than 540°. (gr). If A'B'C' is the polar triangle of ABC...
Page 10 - If a straight line is perpendicular to each of two other straight lines at their point of intersection, it is perpendicular to the plane of the two lines.
Page 57 - COR. The lateral area of a frustum of a regular pyramid is equal to one-half the sum of the perimeters of the bases multiplied by the slant height.
Page 26 - The projection of a point on a plane is the foot of the perpendicular from the point to the plane.
Page 20 - Straight lines which are parallel to the same straight line are parallel to one another.
Page 110 - The distance between two points on the surface of a sphere is the length of the minor arc of a great circle between them.
Page 53 - In any quadrilateral the squares on the diagonals are together equal to twice the sum of the squares on the straight lines joining the middle points of opposite sides.