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