Revision #640 → #1513 · back to history
addedQuadrilateral6c793ab33fda
addedSimple vs. complex quadrilateralsfa7bd1344444
addedInterior angle sum of a quadrilateral46cf760f739d
addedSpecial case of n-gon angle sum67fa1b094e6a
addedQuadrilaterals tile the plane5c18ec307560
addedSimple quadrilateral3e98dcd2f863
addedConvex quadrilateral8df8698c9428
addedIrregular quadrilateral5fab41b762fa
addedTrapezium / trapezoida5a70fde9b0b
addedIsosceles trapezoid742dc1ba7ef4
addedParallelogram65681deff4a2
addedEquivalent conditions for parallelogramaa7e04a43da8
addedEquivalent condition for rhombusd80901061a31
addedRhomboida1076b39ce88
addedRectanglec0456ac97837
addedEquivalent condition for rectangleeb93ec650941
addedSquare iff rhombus and rectangle970eafe6c561
addedKite diagonal properties528b17c52ba0
addedTangential quadrilaterald69dcd73d281
addedPitot characterization of tangential quadrilateral646ae79cc33c
addedTangential trapezoid5364d34e55f8
addedCyclic quadrilateralfba0009c65fe
addedCyclic iff opposite angles sum to 180°b73b00c5b3f0
addedRight kite82b59c1ad7aa
addedHarmonic quadrilateral9cffbaafce74
addedBicentric quadrilateralff1e6d457e33
addedOrthodiagonal quadrilateralafe4ffab1b38
addedEquidiagonal quadrilateral6e6d1471f417
addedBisect-diagonal quadrilateral2d9f0f100439
addedEx-tangential quadrilaterald0d0e802a270
addedEquilic quadrilateral3813bcd54dec
addedWatt quadrilateral7b435dd7ab1d
addedQuadric quadrilateral422280964bf9
addedDiametric quadrilateral3f44b6a08999
addedHjelmslev quadrilateraldf3f3d577583
addedConcave quadrilateral6edce4798945
addedDart (arrowhead)90fecc48923a
addedCrossed (complex) quadrilateral623ac5a48779
addedCrossed quadrilateral interior angle sumda2b704b54ad
addedCrossed trapezoida8b7882463c7
addedAntiparallelogramc060398ab939
addedCrossed rectanglecc85e99f8cf6
addedCrossed squaread8df4aa0275
addedDiagonalsace7c071c8b1
addedBimediansa20b491c2a5a
addedMaltitudesfa27ca11a8b0
addedArea in terms of diagonals and angleceb3b72148ca
addedOrthodiagonal area reductiondd731985de2d
addedArea in terms of bimediansfd5fd1e5d634
addedBretschneider's formula3ba32b366d31
addedReduction to Brahmagupta's formula7bc26a0090a7
addedArea from sides and two anglesc9aed19209e0
addedCyclic case of area formula88b0d9a34276
addedParallelogram case of area formulae1a9512d40a1
addedArea from sides and diagonal intersection angle77100a50fd23
addedParallelogram case of latter formula6a1b79a82cb2
addedArea including sides and midpoint distanceff4f666c74cf
addedLast trigonometric area formula7fb7b2d86c0b
addedArea formula for concave quadrilateral4ca05965bd61
addedArea from sides and diagonals7b4a6e36e198
addedReduction to Brahmagupta's formulabd13e99bf6b7
addedArea from bimedians and diagonals7a5373876a72
addedArea determined by three of bimedians/diagonals48322fe09482
addedArea via cross product of diagonals0473e2ad8aff
addedCartesian form of vector area7846aff071e0
addedTrapezoids with perpendicular diagonals83e196cee81b
addedKite diagonal bisection4e0d708a319b
addedDiagonal lengths via law of cosines3dec2cd3d137
addedSymmetric formulas for diagonal lengths32a4f4150a96
addedEuler's quadrilateral theorem58800fd03a9f
addedBretschneider's generalization of Ptolemy's theoremd662c694a0c9
addedLaw of cosines for a quadrilateral1c4740904e6a
addedRelation from feet of normals to diagonal134b0f5c4384
addedRelation at diagonal intersection pointebb90c0377de
addedShape determined by sides and one diagonal34e4dd96053c
addedCayley-Menger determinant relationb8c2f9aa24d1
addedAngle bisectors form cyclic quadrilateral or concur31e8c74a1d56
addedAngle bisectors meeting on diagonalsbaafe4c20ace
addedBimedianseee07181e80b
addedVarignon parallelogram003342812b0d
addedConcurrency of bimedians and diagonal-midpoint segmentdb898a204be4
addedLength of bimedian connecting sides a and cf153bbabc142
addedLength of bimedian connecting sides b and dd79c0b3e44eb
addedSum of squares of bimedians9b8449fc5c3c
addedBimedians via opposite sides and midpoint distance34f55ff9fc88
addedEqual bimedians iff perpendicular diagonals13ac21b173d2
addedPerpendicular bimedians iff equal diagonals4cb2c7185aa8
addedTrigonometric identities for the four angles8eded85efd7d
addedTangent identity for quadrilateral anglesc2f064184244
addedIdentities with sides and opposite anglesd9e78d001015
addedArea inequalities in terms of sides and diagonals04bb9d8727c3
addedArea bound with perpendicular equal diagonals5a4cb8a1a2a4
addedArea bound from Bretschneider's formula07cea99d07d9
addedArea bound with bicentric/rectangle equality2428a31853dd
addedGeneral area inequality8f34375a07fd
addedArea bound in terms of perimeter1aa92902261a
addedArea bound in terms of diagonalsab6fcc067252
addedArea bound from sides and diagonals1885039097b0
addedArea bound from side lengths2688b62487b5
addedCorollary to Euler's quadrilateral theorem38a16014bcea
addedPtolemy's inequalityaf077ccf1bbd
addedInequality relating bimedians and diagonalse8116e1ff96d
addedInequalities for the sides852107451d45
addedIsoperimetric theorem for quadrilaterals4c78ad2b94bd
addedDual isoperimetric theoremd8de581b946b
addedMaximum area with given sides is cyclic8efd1db598b2
addedMaximum area with given diagonals is orthodiagonalacbdf135c2a8
addedFermat point of a convex quadrilateral1ac43a653257
addedCentres of a quadrilateral409fe2c9f6a4
addedVertex centroid as intersection of bimedians6f385ba50c56
addedArea centroid constructionda3a3380675a
addedQuasicircumcenter, quasiorthocenter and Euler line4486826ea67b
addedQuasinine-point centerb126a2c79974
addedNewton line of a quadrilateral398c47020309
addedVertex centroid divides segment in ratio 3:1110c91f33dbc
addedMiquel point5a26c1bfbb3b
addedPascal pointsaf46149c4824
addedVan Aubel's theorem351d0af0528f
addedExistence of cyclic quadrilateral with same sides48d6c264ab5d
addedProduct of opposite triangle areascccb8d3235b6
addedAngle at diagonal intersection6db8d4a520ca
addedSkew quadrilateral2fbf2ef30df5
addedSkew quadrilateral and tetrahedron correspondence38a696605e86