Concept

Corollary

A corollary is a theorem whose proof is a direct consequence of another theorem, axiom, or definition. For example, the corollary below follows from the Triangle Angle Sum Theorem.

Triangle Angle Sum Corollary

There can be at most one right or obtuse angle in a triangle.

Proofs of corollaries are often short or even not required. Similar to theorems, corollaries can be reasons in a deductive reasoning. Therefore, a corollary can be used in proofs of other corollaries or theorems.

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