9.1Parts of a Circle
Quick Answer
Key circle vocabulary: center, radius, diameter, chord, secant, tangent, arc (minor/major/semicircle), central angle, inscribed angle. The diameter is twice the radius.
Essential Question
How do the key parts of a circle — center, radius, chord, secant, and tangent — relate to each other and to the arcs they intercept?
Learning Goals
- 1Name and identify all parts of a circle.
- 2Distinguish minor arcs, major arcs, and semicircles.
- 3Relate radius, diameter, and chord.
- 4Identify tangent and secant lines.
Key Vocabulary
Radius
A segment from the center to any point on the circle.
Chord
A segment with both endpoints on the circle.
Tangent
A line that intersects a circle at exactly one point.
Secant
A line that intersects a circle at two points.
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.