geometry

6. Points Two points directly opposite each other on a sphere
7. extending or lying across
8. the trigonometric function that is equal to the ratio of the side adjacent to an acute angle (in a right-angled triangle) to the hypotenuse
11. a straight line passing through the center of a circle or sphere and meeting the circumference or surface at each end
13. a line that touches a curve at only one point
14. ratio of the length of the side opposite the given angle to the length of the hypotenuse of a right-angled triangle
15. figure the boundary of a simple two-dimensional region,including shapes with straight and curved sides
17. Triangle A triangle that has no equal sides. All 3 sides are different lengths
18. polygon has no diagonal with points outside the polygon
19. A segment that connects any vertex of a triangle to the midpoint of the opposite side

1. covering of the plane, sometimes referred to as a tiling,referring to the way that tiles cover a floor
2. In a right angle triangle the side of the triangle that is opposite to the right angle
3. a polygon is scalene if its sides are all different lengths
4. Angle The angle cut out of a piece of paper so that the paper can be rolled into a right circular cone
5. Curve a curve that is continuous and has endpoints that meet at the same point
9. Triangle A triangle that has 2 equal sides
10. a quadrilateral with two pairs of adjacent sides with equal lengths
12. triangle a triangle which all the sides are congruent
15. The meeting point of the three medians of a triangle. This point is the center of mass of the triangle
16. The union of a circle and its interior