## Math

##### Across
1. 2. the continuous line forming the boundary of a closed geometric figure.
2. 7. the trigonometric function that is equal to the ratio of the side opposite a given angle (in a right triangle) to the hypotenuse.
3. 8. a triangle) having sides unequal in length.
4. 10. each angular point of a polygon, polyhedron, or other figure.
5. 13. a triangle) having two sides of equal length.
6. 15. a plane figure with 9 straight sides and angles.
7. 19. the quality of being made up of exactly similar parts facing each other or around an axis.
8. 20. a plane figure with four equal straight sides and four right angles.
9. 21. the space (usually measured in degrees) between two intersecting lines or surfaces at or close to the point where they meet.
10. 23. Lying next to each other.
11. 26. The part of a circle made by a line and a connecting arc.
12. 27. a plane figure with at least three straight sides and angles.
##### Down
1. 1. A straight line at an angle of 90° to a given line, plane, or surface.
2. 3. Curved inwards.
3. 4. unproven statement which is supported by all the available data and by many weaker results.
4. 5. a plane figure with seven straight sides and angles.
5. 6. The part of a conditional statement after then.
6. 9. a plane figure with twelve sides.
7. 11. a parallelogram with opposite equal acute angles, opposite equal obtuse angles, and four equal sides.
8. 12. A line with a start point but no end point.
9. 14. 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.
10. 16. a plane figure with eight straight sides and eight angles.
11. 17. a plane figure with three straight sides and three angles.
12. 18. reasoned, logical explanations that use definitions, axioms, postulates, and previously proved theorems to arrive at a conclusion about a geometric statement.
13. 22. A long thin mark made by a pen, pencil, etc.
14. 24. A plane figure with ten straight sides and angles.
15. 25. A result that has been proved to be true.