Across
- 3. Also called half-line. It is a straight line that extends from a point.
- 7. Having one thing on either side of it. 2 is between 1 and 3.
- 8. at least one of the interior angles of a polygon is greater than 180°, it is a concave polygon. The inside surface of a bowl is concave when viewed from above.
- 13. The distance from the center of a circle to any point on its circumference.
- 14. polygon Intuitively speaking, curved away from the eye. A concave figure is a set of points some of whose chords include points that are in the set.
- 15. The length of the boundary around a shape or a figure.For example, the perimeter of a rectangle is twice the sum of its length plus its breadth. The perimeter of a circle is its circumference (2r).
- 19. Lying on the same straight line.
- 20. Postulate is a true statement, which does not require to be proved.
- 21. A polyhedron whose one face is a polygon and the other faces are triangles with one common vertex. This polygon is the base of the pyramid. The other triangles are the lateral faces. The common vertex of these lateral faces is the vertex of the pyramid. The segment from the vertex perpendicular to the base is called the altitude of the pyramid. The length of the altitude is called the height of the pyramid. The intersections of the adjacent lateral faces are called the lateral edges of the pyramid.
- 22. A geometric object that has no dimension and is used to indicate a location.
- 24. A pair of numbers that describe the position of a point on a coordinate plane by using the horizontal and vertical distances from the two reference axes.
- 25. A straight line or a plane that divides a line, a plane, an angle, or a shape into two equal parts.
- 27. In plane geometry, when one figure fits exactly on top of the other through simple translation and/or rotation, then these two figures are congruent.
- 29. A closed plane figure bounded by at least three line segments.
- 30. If the sum of the measures of two angles is 90°, the angles are called complementary. Whenever two angles are complementary, each angle is said to be the complement of the other angle.
- 34. A space figure with two parallel polygonal bases that are the same shape and the same size.
- 35. point P is the initial point or origin of the ray. A ray can be called a closed half-line since it includes the initial point P. An open half-line does not include the initial point P.
- 36. angle An angle with a measure between 0° and 90°.
- 38. angles The pair of angles opposite each other formed by two intersecting lines.
- 40. Often referred to as the right cone. A cone is a solid formed by rotating a right triangle around one of its legs.
- 41. A set of logical arguments used to deduce or prove a mathematical theorem from a set of axioms.
- 42. A unit of measure used to measure the magnitude of an angle, equal in magnitude to 1/360 of a complete revolution.
- 43. segment Part of a line between two points called endpoints.
- 44. A solid bounded by at least four polygonal faces. The pairs of faces meet along their edges. Three or more edges meet in each vertex. A diagonal of a polyhedron is a line segment joining two vertices that are not in the same face.
- 46. angle An angle that measures 90° or /2 radians. It is the angle between two perpendicular lines such as the corner of a square or two perpendicular planes such as the wall and the ground.
- 47. A general conclusion proposed to be proved upon the basis of certain given hypotheses or assumptions; or, a general conclusion that has been proved, e.g., Pythagorean Theorem, Binomial Theorem, Fundamental Theorem of Algebra, etc.
Down
- 1. A line segment that passes through the center of a circle and has its two endpoints on the circle. It also represents the length of such a line segment.
- 2. Also called non-coplanar lines. They are straight lines that are neither parallel, nor intersecting. They lie in different planes.
- 4. The figure formed by two rays from the same initial point. The two rays are called the sides of the angle and the initial point is called the vertex of the angle. The symbol for angle is .
- 5. A point at which the two rays of an angle meet or the intersection point of two sides of a plane figure.
- 6. The surface included within a closed figure, measured by the number of square units needed to cover the surface.
- 9. The side opposite the right angle in a right triangle.
- 10. pair Two angles that are adjacent (share a leg) and supplementary (add up to 180°)
- 11. rays Two rays with a common endpoint that point in opposite directions and form a straight line.
- 12. Points or lines that all lie in the same plane.
- 16. A line segment where two faces of a polyhedron meet.
- 17. The point on a line segment that divides the given line segment into two congruent parts.
- 18. An additional geometric figure that is constructed to assist in solving a problem or producing a proof.
- 21. A flat surface that can extend forever in length and width but has no thickness. The surface of a calm sea and a flat valley are all physical models of a plane.
- 23. Two angles that add up to 180°.
- 24. The boundary line of a circle or the length of such a boundary line.
- 26. A can-shaped solid figure.
- 28. A perfect round ball. A sphere is a closed solid bounded by a surface on which all points are equidistant from a central point called the center.
- 31. Two lines that intersect at right angles.
- 32. angles Two angles that share the same vertex and have one side in common between them.
- 33. A planar surface of a solid figure.The following figure has 5 faces.
- 37. term In geometry, definitions are formed using known words or terms to describe a new word. There are three words in geometry that are not formally defined. These three undefined terms are point, line and plane.
- 39. polygon Intuitively speaking, curved outward or toward the eye. A convex curve is a set of points any of whose chords do not include any point that is not in the set.
- 44. Two or more straight coplanar lines that do not intersect.
- 45. angle An angle that is between 90° and 180°.