Use the central angle measure: the measure of a minor arc equals the measure of its central angle
For a major arc, subtract the minor arc measure from 360°
If two arcs are congruent, they have equal measures
If an inscribed angle intercepts an arc, the arc measure is twice the inscribed angle measure
If an angle is formed by two chords, secants, or tangents, use the appropriate arc-angle relationship to solve for the arc measure
Add adjacent arc measures to find the measure of a larger arc
Use the full circle total: all arcs around a circle add up to 360°