Across
- 2. Proving a conjecture by assuming that the conjecture is false. If this assumption leads to a contradiction, the original conjecture must have been true. This technique employs the logical method known as modus tolens.
- 6. being or operating in the same plane
- 7. An angle that has measure more than 90° and less than 180°.
- 8. Lines in three dimensional space that do not intersect and are not parallel.
- 10. something that is constructed a structure
- 13. An angle whose measure is between 0° and 90° Compare obtuse angle
- 14. in the space separating two points objects
- 17. 4 maths logic mutually exclusive and exhaustive, each being the complement of the other
- 18. a continuous extent of length straight or curved without breadth or thickness the trace of a moving point
- 19. the space within two lines or three or more planes diverging from a common point or within two planes diverging from a common line
- 21. a polygon such that there is a straight line that cuts it in four or more points
- 25. An assertion that can be proved true using the rules of logic. A theorem is proven from axioms, postulates, or other theorems already known to be true.
- 27. a straight line passing through the center of a circle or sphere and meeting the circumference or surface at each end
- 29. Two angles that add up to 180°.
- 33. the side of a polygon
- 34. A line segment between the center and a point on the circle or sphere
- 35. A polyhedron with a polygonal base and lateral faces that taper to an apex. A pyramid with a triangular base is called a tetrahedron.
- 36. A flat surface extending in all directions. Any three noncollinear points lie on one and only one plane. So do any two distinct intersecting lines.
- 37. A pair of adjacent angles formed by intersecting lines. Angles 1 and 2 below are a linear pair. So are angles 2 and 4, angles 3 and 4, and angles 1 and 3. Linear pairs of angles are supplementary
- 39. At a 90° angle.
- 42. a surface or solid bounded by two parallel planes and generated by a straight line moving parallel to the given planes and tracing a curve bounded by the planes and lying in a plane perpendicular or oblique to the given planes
- 44. The geometric figure formed at the intersection of two distinct lines.
- 45. The point halfway between two given points.
- 46. a stage in a scale of relative amount or intensity a high degree of competence
Down
- 1. All points between two given points (including the given points themselves).
- 2. The formula below gives the volume of a solid. A(x) is the formula for the area of cross-sections over the entire length of the solid.
- 3. coinciding at all points when superimposed congruent triangles.
- 4. A statement accepted as true without proof
- 5. A closed plane figure for which all sides are line segments.
- 6. using or pertaining to systems of coordinates
- 9. a polygon such that no side extended cuts any other side or vertex it can be cut by a straight line in at most two points
- 10. the outer boundary especially of a circular area perimeter
- 11. A three dimensional solid consisting of all points equidistant from a given point.
- 12. opposite one another at the intersection of two lines
- 13. two angles having the same vertex and having a common side between them
- 15. any particular extent of space or surface part the dark areas in the painting; the dusty area of the room
- 16. The distance around the outside of a plane figure. For a polygon, the perimeter is the sum of the lengths of the sides.
- 20. a solid whose surface is generated by a line passing through a fixed point and a fixed plane curve not containing the point consisting of two equal sections joined at a vertex
- 22. Alternate exterior angles are congruent. Formally, alternate exterior angles are defined as two exterior angles on opposite sides of a transversal which lie on different parallel lines.
- 23. lying in the same straight line
- 24. line that extends from a vertex of a triangle to the opposite side (which may be extended). Medians, altitudes, and angle bisectors are all examples of cevians.
- 26. unknown angle
- 28. the side of a right triangle opposite the right angle
- 30. A solid with parallel congruent bases which are both polygons
- 31. a line or border at which a surface terminates
- 32. A part of a line starting at a particular point and extending infinitely in one direction.
- 38. a line or plane that bisects an angle or line segment
- 40. One of the flat surfaces making up
- 41. A 90° angle.
- 43. A corner point of a geometric figure.