math words

2. a straight line from the center to the circumference of a circle or sphere.
5. is the angle that forms when two radii meet at the center of a circle.
6. The region between two concentric circles of different radii is called an annulus
8. the enclosing boundary of a curved geometric figure, especially a circle.
11. a straight line that touches a point.
12. commonly refers to a line that intersects a circle at exactly two points.

1. a straight line passing from side to side through the center of a body or figure, especially a circle or sphere.
3. a half of a circle or of its circumference.
4. angle formed by two chords in a circle which have a common endpoint.
7. the numerical value of the ratio of the circumference of a circle to its diameter
8. a group of (typically three or more) notes sounded together, as a basis of harmony.
9. a ring-shaped object, structure, or region.
10. the middle point of a circle or sphere, equidistant from every point on the circumference or surface.
13. a part of the circumference of a circle or other curve.