Mathematics 7 Undefined Terms Quiz

Undefined Terms

• Undefined terms are described through examples and visual representations, lacking a formal description.
• There are three undefined representation terms: Point, Line, and Plane.

Point

• A point is represented by a dot.
• A point is labeled by a capital letter (e.g., point A, point M, point X).
• A point shows a specific location.
• A point has no length, width, or thickness.
• Examples of points include a person's mole, the tip of a pencil.

Line

• A line is represented by the symbol →.
• A line can be named by two capital letters (e.g., line AC or line m).
• A line can also be labeled by a small italicized letter near the arrowhead.
• A line has length but no width or thickness.
• A line always extends indefinitely in two directions.
• A double-headed arrow is placed over the name of the line.
• A line is made up of infinite points.

Collinear and Noncollinear Points

• Collinear points are points that lie on the same straight line.
• Examples of collinear points include points D, I, G, and F.
• Noncollinear points are points that are not all on the same straight line.
• Examples of noncollinear points include points D, I, L and points L, K, and M.

Concurrent Lines

• Concurrent lines are lines that meet at a single point.
• The point of concurrency is a point where three or more lines intersect.
• Examples of concurrent lines include lines n, v, r, and t.

Intersecting Lines

• Intersecting lines are two lines that meet at a single point.
• Examples of intersecting lines include lines v and t, and lines n and t.
• A point that is common to the two intersecting lines is called the point of intersection.

Perpendicular Lines

• Perpendicular lines are lines that intersect each other at right angles (90°).
• Example: line n ⊥ line r.
• A point that is common to the two perpendicular lines is called the point of intersection.

Parallel Lines

• Parallel lines are lines that do not intersect or meet each other at any point in a plane.
• Parallel lines are equidistant from each other.
• Example: lines f and d are parallel.

Plane

• A plane is a flat surface.
• A plane can be labeled by three points on the plane (e.g., Plane LRG).
• A plane can also be labeled by a capital italicized letter near the arrowhead.
• A plane has width and infinite length but no thickness.
• A plane extends infinitely in all directions.
• Examples of planes include the surface of a blackboard.

Coplanar and Noncoplanar Points

• Coplanar points are points that are on the same plane.
• Examples of coplanar points include points L, F, R, and S.
• Noncoplanar points are points that are not all on the same plane.
• Examples of noncoplanar points include points L, F, R, and Q, and points T, P, R, and L.