Key Idea: Arc Length
The arc length of a circle is a fraction of the circumference, determined by the measure of the central angle relative to the entire circle.
General Rule:
Arc Length = Central Angle / 360 × CircumferenceWhy this matters for the SAT:
Arc length problems often appear in circle geometry. Recognizing that arc length depends on the angle-to-360° ratio allows you to solve quickly without memorizing multiple formulas.