ANGLES

• Acute angle


  Below 90 degrees
• Right angle


  Equal to 90 degrees
• Obtuse angle


  Larger than 90 degrees but less than 180 degrees
• Straight angle


  Equal to 180 degrees
• Complementary angles


  Angles that add up to 90 degrees
• Supplementary angles


  Angles that add up to 180 degrees
• Line


  A straight path of points that has no beginning or end
• Ray


  Contains one end point and extends forever in one direction
• Segment


  A portion of a line that has two endpoints
• Intersecting lines


  Lines that come together at a point
• Perpendicular lines


  Two lines which intersect at right angles (90 degrees)
• Parallel lines


  Two or more lines that are the same distance apart and never meet
• Transversal line


  Lines that cross two or more lines
• Corresponding angles


  Angles in the same side, one interior and one exterior, but not adjacent
• Alternate interior angles


  Two angles on different sides formed INSIDE two parallel lines
• Alternate exterior angles


  Two angles on different sides formed OUTSIDE two parallel lines
• VERTICAL ANGLES

  a=b

  c=d

  
• Corresponding angles :

  a=e

  b=f

  c=g

  d=h

  Alternate interior

  c=f

  d=e

  Alternate exterior

  a=h

  b=g