W1

• Angle


  Formed with two non-collinear rays and the common endpoint of the two rays is the vertex
• Right angle


  A type of angle which is exactly measured at 90°
• Acute angle


  A type of angle that is less than 90°
• Obtuse angle


  A type of angle that is greater than 90° but less than 180°
• Circle


  The set of all points in a plane at a given distance (radius) from a given point (center) in the plane
• Radius

  A line segment from the center to any point of the circle
• Chord

  A line segment whose endpoints lie on the circle
• Diameter


  A chord containing the center
• Arc


  Two points on the circle and the continuous part of the circle between the two points. The two points are called the endpoints of the arc. Arc measure is found by measuring the central angle
• Semicircle


  An arc of a circle whose endpoints are points of the diameter
• Minor arc


  An arc of a circle that is smaller than a semicircle
• Major arc


  An arc of a circle that is larger than a semicircle
• Inscribed Angle


  The angle if a circle subtended at a point on the circle by two given points on the circle
• Secant


  A line that intersects the circle at two points. It contains a chord
• Tangent

  A line lying on the same plane as the circle that intersects the circle in exactly one point. The point where the tangent touches the circle is called point of tangency
• Polygon

  A two-dimensional geometrical closed figure formed by at least three line segments connected end to end
• Sides


  The line segments that connect two consecutive vertices (of a polygon)
• Vertices


  The intersections of the endpoints of the segments or sides (of a polygon)
• Diagonals


  The segments that connect two non-consecutive vertices (of a polygon)
• Convex polygon

  A polygon where none of its diagonals is in the exterior of the polygon
• Concave polygon


  A polygon where at least one of its diagonals is in the exterior of the polygon
• Equilateral polygon

  A polygon where all of its sides have equal lengths
• Equiangular polygon

  A polygon where all of its angles are congruent or have equal angle measures
• Regular polygon


  A polygon that is both equilateral and equiangular
• Consecutive vertices


  The endpoints of a side of a polygon
• Consecutive angles


  Two angles of a polygon that have a common side
• Consecutive sides


  Two sides of a polygon that have a common vertex
• Transversal

  A line intersecting two or more coplanar lines at different points
• Complementary angles

  Two angles where the sum of their measures is 90°
• Supplementary angles

  Two angles where the sum of their measures is 180°
• Adjacent angles

  Two angles with a common vertex, a common side and no common interior points
• Linear pair

  Two angles that are both adjacent and supplementary
• Congruent angles

  Two angles with equal measures
• Vertical angles

  Angles formed when two straight lines intersect each other, where their sides form two pairs of opposite rays and their angles are non-adjacent
• Perpendicular lines

  Lines that intersect at right angles
• Parallel lines


  Coplanar lines that do not intersect