Category:三角形と円に関する定理

Thales's theorem

Musselman's theorem

Van Schooten's theorem

Cramer–Castillon problem

Simson line

Van Lamoen circle

Feuerbach's theorem

Six circles theorem

Incenter–excenter lemma

Euler's theorem in geometry

Carnot's theorem (inradius, circumradius)

Polar circle (geometry)

Reuschle's theorem

Fuhrmann circle

Kosnita's theorem

Miquel's theorem

Lester's theorem

Harcourt's theorem

Pompeiu's theorem

Thébault's theorem

Japanese theorem for cyclic polygons

Lune of Hippocrates

Lexell's theorem

Griffiths' theorem

Conway circle theorem