Radian Measure and The Unit Circle
percent
(part/whole)X100
θ
Theta (used in trigonometry to represent an angle)
Cos θ (cosine)
adjacent leg/hypotenuse x/r
central angle
an angle formed inside a circle with the center as its vertex
Cot θ (cotangent)
cos θ/sin θ x/y 1/tan θ
Sec θ (secant)
1/cos θ hyp/adj
Csc θ (cosecant)
1/sin θ r/y
Circumference
C= 2πr (the distance around a circle)
270⁰ or 3π/2
The number of degrees in three-fourths of a circle
360⁰ or 2π
The number of degrees/radians in a complete circle
90⁰ or π/2
The number of degrees/radians in a fourth of a circle
180⁰ or π
The number of degrees/radians in a half of a circle (a semicircle)
60⁰ or π/3
The number of degrees/radians in one-sixth of a circle
120⁰ or 2π/3
The number of degrees/radians in one-third of a circle
radian measure
The radian measure of an angle is the ratio of the arc length to the central angle.
Rationalizing the denominator
getting rid of a radical in the denominator
what does "of" mean in math
multiply
conversion to degrees
multiply by (180⁰/π)
conversion to radians
multiply by (π/180⁰)
Tan θ (tangent)
opposite leg/adjacent leg y/x
Sin θ (sine)
opposite leg/hypotenuse y/r
fraction
part/whole
arc length
the length of an arc; a piece of the circumference of a circle; s=rθ where θ MUST be in radians