9.2Central Angles and Arcs
Quick Answer
A central angle equals its intercepted arc. Arc Addition Postulate: adjacent arcs add. Congruent circles have congruent central angles iff they have congruent arcs.
Essential Question
How does a central angle determine the measure of its intercepted arc, and how does the Arc Addition Postulate let you find arc measures in complex diagrams?
Learning Goals
- 1Define central angle and intercepted arc.
- 2State that a central angle equals its intercepted arc.
- 3Apply the Arc Addition Postulate.
- 4Find arc measures in diagrams with multiple arcs.
Key Vocabulary
Central angle
An angle whose vertex is the center of the circle; its measure equals its intercepted arc.
Arc Addition Postulate
The measure of an arc formed by two adjacent arcs equals the sum of their measures.
Full lesson content coming soon
Worked examples, guided practice problems, a workbook, quiz, and downloadable PDF resources will be added to this lesson in Phase 2. The learning goals and vocabulary above reflect the complete lesson scope.