Math Crossword

5. a circle is a straight line segment whose endpoints both lie on the circle.
6. any smooth curve joining two points.
7. a secant of a curve is a line that intersects the curve in at least two (distinct) points.
8. by an arc between those two points, and the arc length is the central angle of a circle of radius one.
10. an angle formed by two chords in a circle which have a common endpoint.
12. a straight line from the center to the circumference of a circle or sphere.
13. the middle point of a circle or sphere

1. a half of a circle or of its circumference
2. a plane curve at a given point is the straight line that "just touches" the curve at that point.
3. the enclosing boundary of a curved geometric figure, especially a circle.
4. circles with a common center.
6. a ring-shaped object, structure, or region.
9. a mathematical constant.
11. a straight line passing from side to side through the center of a body or figure, especially a circle or sphere.