Circle Vocab
Chapter 10
1. Center: the name of a circle, all points are equidistant from here.
2. Radius: from center to edge.
3. Diameter: from edge to edge through the center
4. Central Angle: Vertex is the center of the circle.
5. Semicircle: half of a circle
6. Minor Arc: Smaller than a semicircle
7. Major Arc: Larger than a semicircle
8. Arc Addition Postulate: just like segments, arcs can be summed
9. Circumference: Distance around the circle
10. Concentric circles: Circles in the same plane. (think a bullseye!)
11. Arc Length: measured in degrees, the fraction of the circle’s circumference *formula
of green sheet!*
12. Sector: region bounded by an arc with two radii endpoints. (like a slice of pie)
13. Segment: region bounded by an arc not going through the center
14. Geometric Probability: allowing points to represent outcomes
Chapter 12
15. Tangent Line: line that intersects the circle just once, perpendicular to the radius at
that point
16. Point of tangency: the point where the circle and tangent intersect
17. Chord: Line that makes up a segment, not through the center