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revolution
a common unit for measuring very large angles; 1 revolution is a complete circular motion
degree
a common unit for measuring smaller angles; 1 revolution = 360°
radian measure
another way to measure small angles
angle in standard position
has a vertex at the origin and the initial ray lies on the positive x-axis
quadrantal angles
where the circle intersects the x and y-axis
coterminal angles
two angles in standard position that have the same terminal ray
sector
the region bounded by the central angle and the intercepted arc
arc length
a fraction of the circumference
reference angles
angles in different quadrants that have the same trig ratios [although the signs may be different]
initial ray
the starting ray
terminal ray
the ray created after moving by θ
arc length in radian
s=θr
arc length in degrees
s=(θ/180°)πr
area of a sector w/radians
k=½θr²
area of a sector w/degrees
k=(θ/360°)πr²
area of a sector w/arc length & radius
k=½sr
sinθ
y; y/r
cosθ
x; x/r
equation of unit circle
x² + y² = r²
degree to radians
___° × (π/180°)
radians to degrees
___ rad × (180°/π)
Note 
Flashcard (54)