Category:三角形と円に関する定理

Japanese theorem for cyclic polygons

Musselman's theorem

Miquel's theorem

Van Schooten's theorem

Cramer–Castillon problem

Van Lamoen circle

Pompeiu's theorem

Six circles theorem

Incenter–excenter lemma

Thébault's theorem

Euler's theorem in geometry

Carnot's theorem (inradius, circumradius)

Polar circle (geometry)

Reuschle's theorem

Fuhrmann circle

Kosnita's theorem

Feuerbach's theorem

Harcourt's theorem

Lester's theorem

Lune of Hippocrates

Lexell's theorem

Griffiths' theorem

Conway circle theorem

Simson line

Thales's theorem