The Essentials of Geometry (plane)

AC and BC AC² AD² adjacent angles altitude angles are equal apothem approach the limit arc BC base and altitude BC² bisector bisects centre cents chord circumference circumscribed common point construct the triangle Converse of Prop decagon diameter Draw line EFGH equal angles equal respectively equally distant equiangular polygon equilateral triangle equivalent exterior angle figure Given line given point given square given straight line homologous sides hypotenuse isosceles triangle line CD line joining middle point non-parallel sides number of sides one-half opposite sides parallel parallelogram perimeter perpendicular points of sides polygons AC produced Proof Prove ABC Prove Prop quadrilateral radii radius ratio rectangle regular inscribed regular polygon rhombus right angles right triangle secant segment side BC similar triangles subtended tangent THEOREM transversal trapezoid triangle is equal vertex