Trigonometry Exam 1

Trigonometry Exam 1

1. An angle is formed by 2 rays having a common starting point

   • A ray is a part of a line with only one endpoint and continues forever in the direction it's heading.
   • Angles are measured using Degrees, Radians, Gradians and Revolutions
     • Degrees are 1/360th of a Revolution
       • 180 degrees = π radians
         • x degrees = xπ radians/180° = x radians
     • A radian is a unit of measure based on radius length 1 revolution = 2π
       • π radians = 180 degrees
         • x radians = 180°x/π radians = x degrees
     • gradians are 1/400th of a revolution
     • 1 revolution = 360 Degrees, 400 Gradians, 2π radians.
   • Directionality determines whether an angle is positive or negative
     • Counterclockwise = Positive
     • Clockwise = Negative
   • Standard position is the the initial side is on the x-axis
     • Initial side is the starting side of the angle. Doesn't move.
     • Terminal side moves and is the ending side of an angle
       • Co-terminal angles are 2 angles that have the same terminal side. (they subtract to be a multiply of 360°,2π radians,400 gradians, or 1 revolution)
   • Complementary angles add up to 90°
   • Supplementary angles add up to 180°

2. Degree+(Minute/60)+(Second/3600) = Degrees

   • Degrees's decimal * 60 = Minutes. Minute's decimal*60 = Seconds → Degrees = Degrees, Minutes, Seconds