# Concept derivation guides

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Concept guide



## [Angle: a step-by-step proof that vertical angles are equal](/en/derivations/derivation-mko-angle-01/?from=%2Fen%2Fderivations%2F%3Fq%3Dmko-angle)

Distinct lines AB and CD meet at O, with O between A and B and between C and D. Prove that vertical angles are equal: m∠AOC=m∠BOD and m∠COB=m∠DOA; then, for m∠AOC=35°, compute all four angles.

Angle

derivation-mko-angle-01





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