Stage 18 · Circles

18.2.2 The Measure of an Arc

18.2 The Three-Way Conversation Between Angle, Arc, and Chord

Point 2 of 4

18.2.2 The Measure of an Arc

Core idea

Treat the whole rim as 360 degrees, and however many degrees the central angle facing an arc measures, that is exactly the measure of the arc.

Module goal. Build the equal relationships among a central angle, the arc it faces, and the chord it cuts, so that angle, arc, and chord can all be converted into one another.
eastmath.com · 18.2 The Three-Way Conversation Between Angle, Arc, and Chord · 18.2.2 The Measure of an Arc