Geometry

• Undefined Terms in Geometry

  • Point
  • Line
  • Plane
• Point


  A fundamental building block in geometry, represented by a dot, indicating a specific location in space without any size or dimension
• Line


  A straight, continuous arrangement of infinitely many points extending indefinitely in both directions. It has no width or thickness
• Plane


  A flat, two-dimensional surface that extends infinitely in all directions and is defined by an infinite number of lines
• Subsets of Line


  • Line Segment
  • Ray
  • Line
• Line Segment


  A part of a line that consists of two endpoints and all the points between them
• Ray


  A part of a line that has one endpoint and extends infinitely in one direction
• Line


  The entire straight path that extends indefinitely in both directions
• Kinds of Angles and Angle Pairs

  • Acute Angle
  • Right Angle
  • Obtuse Angle
  • Straight Angle
  • Vertical Angles
  • Adjacent Angles
• Acute Angle


  An angle that measures less than 90 degrees
• Right Angle


  An angle that measures exactly 90 degrees
• Obtuse Angle


  An angle that measures more than 90 degrees but less than 180 degrees
• Straight Angle


  An angle that measures exactly 180 degrees, forming a straight line
• Vertical Angles

  Two non-adjacent angles formed by the intersection of two lines. They are congruent, meaning they have the same measure
• Adjacent Angles


  Two angles that share a common side and a common vertex but do not overlap
• Transversal


  In geometry, a transversal is a line that intersects two or more other lines at distinct points
• Polygons


  • Convex Polygon
  • Concave Polygon
• Convex Polygon


  A polygon in which all interior angles are less than 180 degrees, and all diagonals lie inside the polygon
• Concave Polygon


  A polygon that has at least one interior angle greater than 180 degrees, resulting in at least one diagonal lying outside the polygon
• The sum of the interior angles of a polygon with (n) sides is given by the formula (n-2)×180) degrees
• Interior Angles of a Polygon

  The angles inside the polygon formed by its sides
• Exterior Angles of a Polygon

  The angles formed outside the polygon when one side is extended