Circle geometry

1 article

Annulus Antarctic circle Apollonian circles Arbelos Archimedean circle Archimedes quadruplets Arctic circle Area of a circle Area of a disk Bankoff circle Benz plane Bertrand's paradox probability Bonnesen inequality Borromean rings Brahmagupta's formula Buffon's needle Bundle theorem Butterfly theorem Casey's theorem Center pivot irrigation Central angle Centrifugal force Centripetal force Chord Circle criterion Circle inversion Circle map Circle of a sphere Circle of antisimilitude Circle of confusion Circle of forces Circle of latitude Circle points segments proof Circles in polish mythology Circles of apollonius Circular dichroism Circular distribution Circular ditches Circular orbit Circular sector Circular segment Circular slide rule Circular statistics Circumscribed circle Cliffords circle theorems Coaxal circles Coaxial Compass drafting Concentric Concyclic Coxeters loxodromic sequence of tangent circles Crescent Crop circle Deferent and epicycle Descartes theorem Dinostratus theorem Dip circle Director circle Disk Dividing a circle into areas Dotted circle Droz farny line theorem Enso Epitrochoid Equator Fermatapollonius circle Filling radius Five circles theorem Fuhrmann circle Generalised circle Geos circle Goat grazing problem Great circle Great circle distance Hadamard three circle theorem Hardylittlewood circle method Hawaiian earring Hazards of outdoor activities Horn angle Hypotrochoid Inscribed angle Inscribed angle theorem Inscribed circle Inversive distance Irrational rotation Lazy caterers sequence Limiting cases of apollonius problem Lune Lune of hippocrates Magic circle Malfatti circles Mean of circular quantities Measurement of a circle Milne thomson circle theorem Mohr's circle Mohrmascheroni theorem Monges theorem Mrs minivers problem Non uniform circular motion Olympic symbols Orthocentroidal circle Osculating circle Ouroboros Overlapping circles grid Peaucellierlipkin linkage Petosiris to nechepso Pi Pitch circle Pizza theorem Polar circle Pole and polar Poncelet's porism Ponceletsteiner theorem Position circle Power center Power of a point Problem of apollonius Ptolemy's table of chords Ptolemy's theorem Quasicircle Quatrefoil Radical axis Radius Radius bone Radius of convergence Repeating circle Ring diacritic Ring lemma Roundel Sacred chao Salinon Schinzel circle Schoch circles Secant line Semicircle Setting circles Seven circles theorem Six circles theorem Soddy's hexlet Solar symbol Splitting circle method Squared circle postmark Squaring the circle Squircle Steam locomotive Steiner chain Stone circle Sun cross Tammes problem Tangent circles Tangent lines to circles Tanit Tarski's circle squaring problem Taylor circle Thales theorem Thomas baxter mathematician Thomson problem Timber circle Traffic circle Trefoil Triple goddess neopaganism Tropic of cancer Tropic of capricorn Twin circles Uniform circular motion Van lamoen circle Vesica piscis Villarceau circles Von mises distribution Wheel Wigner semicircle distribution Woo circles Wrapped cauchy distribution Wrapped distribution Wrapped normal distribution Yin and yang

Probability & Statistics LicenceExplication9 min

Pourquoi les triangles aléatoires attrapent le centre du cercle une fois sur quatre

Placez trois points au hasard sur un cercle et le triangle contient le centre exactement une fois sur quatre. Deux preuves : une moyenne honnête, puis deux pièces déguisées en géométrie.