Across
- 5. a triangle with at least two equal sides
- 9. the length of a straight line though the center of a circle
- 10. the length of the closed curve of a circle
- 11. a line segment extending from the center of a circle or sphere
- 12. a polygon with 5 sides and 5 angles
- 13. the middle point of the line segment
- 14. an angle between 90 and 180 degrees
- 17. a plane figure with at least three straight sides and angles
Down
- 1. a round three dimensional closed surface
- 2. a triangle with three acute angles
- 3. two angles or arcs whose sum is 180 degrees
- 4. a solid figure bounded by plane polygons or faces
- 6. a two dimensional collection of points
- 7. at an angle of 90* to a given line, plane or surface
- 8. a branch of mathematics concerned with the relations of points, lines,surfaces etc
- 15. all points on the straight path between two points
- 16. a particular aspect of life or activity