## A Text-book of Geometry |

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ABCD altitude axis base bisector bisects called centre chord circumference circumscribed coincide common cone construct curve cylinder denote diagonal diameter dihedral angles directrix distance divide draw ellipse equal respectively equidistant equilateral triangle equivalent face angles feet Find the area frustum given circle given line given point given straight line greater Hence homologous sides hypotenuse inches inscribed intersection isosceles lateral area lateral edges latus rectum middle point number of sides opposite parabola parallel parallelogram parallelopiped perimeter perpendicular plane MN plane passed polyhedral angle polyhedron prism prove Proof Q. E. D. PROPOSITION radii radius ratio rectangle regular polygon right angle right circular right triangle SCHOLIUM secant segment similar polygons slant height sphere spherical polygon spherical triangle square surface tangent tetrahedron THEOREM triangle ABC triangular prism trihedral vertex vertices

### Popular passages

Page 88 - Any two sides of a triangle are together greater than the third side.

Page 340 - A spherical angle is measured by the arc of a great circle described from its vertex as a pole and included between its sides (produced if necessary). Let AB, AC be arcs of great circles intersecting at A; AB...

Page 61 - The exterior angles of a polygon, made by producing each of its sides in succession, are together equal to four right angles.

Page 323 - The volume of a frustum of a cone is equivalent to the sum of the volumes of three cones whose common altitude is the altitude of the frustum and whose bases are the lower base, the upper base, and a mean proportional between the bases of the frustum.

Page 179 - Two triangles having an angle of the one equal to an angle of the other are to each other as the products of the sides including the equal angles.

Page 56 - The straight line joining the middle points of two sides of a triangle is parallel to the third side and equal to half of it 46 INTERCEPTS BY PARALLEL LINES.

Page 140 - If two triangles have an angle of the one equal to an angle of the other, and the including sides proportional, they are similar. In the triangles ABC and A'B'C', let ZA = Z A', and let AB : A'B' = AC : A'C'. To prove that the A ABC and A'B'C' are similar. In this case we prove the A similar by proving them mutually equiangular. Proof. Place the A A'B'C...

Page 126 - If four quantities are in proportion, they are in proportion by composition; that is, the sum of the first two terms is to the second term as the sum of the last two terms is to the fourth term.

Page 346 - 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 342 - A spherical polygon is a portion of the surface of a sphere bounded by three or more arcs of great circles. The bounding arcs are the sides of the polygon ; the...