Category:三角形と円に関する定理

Thales's theorem

Lune of Hippocrates

Musselman's theorem

Miquel's theorem

Van Schooten's theorem

Incenter–excenter lemma

Lester's theorem

Harcourt's theorem

Cramer–Castillon problem

Six circles theorem

Thébault's theorem

Euler's theorem in geometry

Carnot's theorem (inradius, circumradius)

Polar circle (geometry)

Reuschle's theorem

Fuhrmann circle

Kosnita's theorem

Van Lamoen circle

Pompeiu's theorem

Lexell's theorem

Griffiths' theorem

Conway circle theorem

Simson line

Feuerbach's theorem

Japanese theorem for cyclic polygons