Similar to タレスの定理

Law of tangents

Analyticity of holomorphic functions

Linear independence

Diagonal lemma

Monotone convergence theorem

Intermediate value theorem

Parallelogram law

Taylor's theorem

Dirichlet integral

De Moivre's formula

Ptolemy's theorem

Sz.-Nagy's dilation theorem

Seven circles theorem

Napkin ring problem

Lazy caterer's sequence

Newton's theorem (quadrilateral)

Proof that e is irrational

Hardy–Littlewood inequality

Pappus's area theorem

Pappus's hexagon theorem

Banach–Alaoglu theorem

Banach fixed-point theorem

Tangent half-angle substitution

Pythagorean theorem

Nyquist–Shannon sampling theorem

Fatou's lemma

Bézout's identity

Petr–Douglas–Neumann theorem