Angles

• Acute


  measures below 90°
• Right


  equal to 90°
• Obtuse


  larger than 90° but less than 180°
• Straight


  180°
• Supplementary

  Angles that add up to 180°
• Complementary

  Angles that add up to 90°
• Vertical

  Angles that are equal
• ∪

  Union
•  ∩

  Intersection
• Two rays is called

  Angle
• ||

  Parallel
• ⊥

  Perpendicular
• When finding the another slope of perpendicular lines, you have to reciprocate the given slope, then change the sign
• Alternate Interior Angles 


  Inside of the two parallel lines but they're opposite of the transversal; they are congruent
• Alternate Exterior Angles


  Outside of the two parallel lines and they alternate to the transversal; they are congruent(or the same)
• Consecutive Interior Angles 


  means the next one after; they are supplementary
• Corresponding angles

  Same side, one interior, one exterior but not adjacent;they are congruent
• Opposite Angles are the same
• Adjacent Angles sum up to 180°
• Angle of Depression


  When you see an object below you, the angle of depression is between the horizontal and your line of sight to the object
• Angle of Elevation


  When you see an object above you, the angle of elevation is between the horizontal and your line of sight to the object