## MATH

##### Across
1. 4. a straight line that touches the outside of a curve but does not cross it
2. 5. “to cut”
3. 7. a line that goes around a circle or any other curved shape; the length of this line
4. 9. half of the diameter
5. 10. a flat shape with eight straight sides and eight angles
6. 13. triangle with the same side length on two sides
7. 15. the portion of a circle enclosed by two radii and an arc
8. 16. a flat shape with ten straight sides and ten angles
9. 18. the point where the internal angle bisectors of the triangle cross
10. 20. triangle with the same side length on three sides
11. 21. the intersections of the triangles’ medians
12. 22. two circles only contact on one point, and they are on the different side
13. 25. the set of points which are an equal distance to a fixed point
14. 29. of a regular polygon is a line segment from the center to the midpoint of one of its sides
15. 31. a flat shape with twelve straight sides and twelve angles
16. 33. two unparallel lines may have
17. 34. having four straight equal sides and four angles of 90°
##### Down
1. 1. a flat shape with three straight sides and three angles
2. 2. the angle inside two adjacent sides of a polygon
3. 3. two circles only contact on one point, and they are on the same side
4. 6. the intersections of the triangles’ angular bisectors is the center of the circle
5. 8. the vertexes of the triangles are all on the circle
6. 11. a flat shape with four straight sides
7. 12. a straight line going from one side of a circle or any other round object to the other side, passing through the centre
8. 14. 180°- interior angle
9. 17. 90°
10. 19. a flat shape with six straight sides and six angles
11. 23. polygon with the same interior angles and sides’ lengths.
12. 24. a flat shape with nine straight sides and nine angles
13. 26. dividing something into two equal parts
14. 27. a flat shape with at least three straight sides and angles, and usually five or more
15. 28. a line segment joining two points on a curve
16. 30. a flat shape with five straight sides and five angles
17. 32. a flat shape with seven straight sides and seven angles