The Elements of Geometry

ABC and DEF ABCD adjacent angles altitude angles are equal approach the limit arc BC area ABC bisector bisects centre chord circle circumference circumscribed cone of revolution construct the triangle Converse of Prop cylinder denote diagonals diameter diedral Draw AC equal respectively equally distant equilateral triangle equivalent exterior angle Find the area frustum given point given straight line Hence homologous hypotenuse intersection isosceles triangle lateral area lateral edges Let ABC measured by arc middle point number of sides parallelogram parallelopiped perimeter perpendicular to MN plane MN polyedral polyedrons prism produced PROPOSITION prove pyramid quadrilateral radii radius rectangle regular polygon rhombus right angles right triangle secant secant line segment similar slant height sphere spherical polygon spherical triangle square surface tangent tetraedron THEOREM trapezoid triangle ABC triangles are equal triangular prism triedral vertex vertices volume Whence