A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site GEOMETRY    • acute    • adjacent    • affine geometry    • alternate    • altitude    • angle    • annulus    • apex    • apothem    • Apollonius problem    • arc    • area    • asymptote    • Aubel's theorem    • axis of symmetry    • Bang's theorem    • bisect    • bisecting an angle    • Blanche's dissection    • Brianchon's theorem    • butterfly theorem    • cannonball problem    • cathetus    • Cavalieri's principle    • center of perspective    • central angle    • centroid    • chord    • circumcenter    • circumference    • circumscription    • commensurable    • compasses    • congruent    • constructible    • coplanar    • cosine rule    • curvature    • curvature tensor    • curve    • de Malve's theorem    • Descarte's circle theorem    • diagonal    • diameter    • differential geometry    • dihedral angle    • dimension    • dissection    • duplicating the cube    • equichordal point    • equilateral    • elliptical geometry    • Euclidean geometry    • Euclidean space    • Euclid's postulates    • Euler line    • Fagnano's problem    • Flatland    • focal chord    • focal radius    • focus    • four coins problem    • fourth dimension    • geodesic    • geometry    • Gergonne point    • great circle    • Hadwiger problem    • half-line    • half-plane    • harmonic division    • Hero's formula    • higher dimensions    • hole-through-a-sphere problem    • hyperbolic geometry    • hypercube    • hypotenuse    • inscribed angle    • isogonal conjugate    • isometry    • isoperimetric inequality    • isosceles    • isotomic conjugate    • isovolume problem    • Johnson's theorem    • Kakeya needle problem    • Kakeya needle problem    • Langley's adventitious angles    • latus rectum    • line    • loculus of Archimedes    • locus    • major axis    • Mascheroni construction    • metric    • midpoint    • minor axis    • Morley's miracle    • moving sofa problem    • Nagel point    • Neusis construction    • nine-point circle    • non-Euclidean geometry    • normal    • oblique    • obtuse    • orthocenter    • orthogonal    • osculating    • packing    • parallel    • parallel postulate    • Pascal's mystic hexagon    • perimeter    • periphery    • perpendicular    • Pick's theorem    • plane    • point    • polytope    • Poncelet's theorem    • Prince Rupert's problem    • projective geometry    • prolate    • Ptolemy's theorem    • Pythagoras's theorem    • quadrature    • radical axis    • radius    • ray    • reentrant angle    • reflection    • reflex angle    • right    • rope-around-the-Earth puzzle    • rotation    • ruler-and-compass construction    • salient    • secant    • sector    • segment    • self-intersecting    • similar    • six circles theorem    • skew lines    • Soddy's formula    • Sperner's lemma    • squaring the circle    • squaring the square    • Steiner-Lehmus theorem    • straight    • supplementary angles    • Sylvester's problem of collinear points    • symmedian    • tangent    • transformation    • translation    • transversal    • trigonometric function    • trigonometry    • trisecting an angle    • trisector theorem    • two-dimensional worlds    • unilluminable room problem    • vertex    • Viviani's theorem    • volume Related categories    • ANALYTICAL GEOMETRY    • GAMES AND PUZZLES    • PLANE CURVES    • POLYGONS    • SPACE AND TIME Related supercategory    • MATHEMATICS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP