Similar to 三平方の定理

Carnot's theorem (perpendiculars)

Stewart's theorem

Law of sines

Law of tangents

Ceva's theorem

Midpoint theorem (triangle)

Desargues's theorem

Thomsen's theorem

Droz-Farny line theorem

Napoleon's theorem

Pappus's area theorem

Feuerbach hyperbola

Heron's formula

Bottema's theorem

Maxwell's theorem (geometry)

Menelaus's theorem

Morley's trisector theorem

Jacobi's theorem (geometry)

Law of cosines

Law of cotangents

Routh's theorem