Angle Addition Postulate — Foundational Geometric Concepts + 4 more topics

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The Angle Addition Postulate is a straightforward concept: if point B lies in the interior of angle AOC, then the measure of angle AOB plus the measure of angle BOC equals the measure of angle AOC. In simpler terms, a larger angle is made up of the sum of the smaller angles inside it.

You'll see this written as: $m\angle AOB + m\angle BOC = m\angle AOC$.

Here, $m\angle$ just means "the measure of angle".