# Nagel's Theorem

Nagel's Theorem

Let ABC be a triangle with two altitudes AA' and BB', and let O be the center of the circumcircle. Then A'B' and CO are perpendicular.

WOLFRAM|DEMONSTRATIONS PROJECT

Nagel's Theorem

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Let ABC be a triangle with two altitudes AA' and BB', and let O be the center of the circumcircle. Then A'B' and CO are perpendicular.