Degrees of a Unit Circle

Convert the following to degrees:
-8π/5 radians

• -288⁰

• -260⁰

• -275⁰

sin 210°

cos 90°

• 0

• 1

• -1

• undefined

cos 135°

• √2/2

• -√2/2

• √3/2

• -√3/2

sin 180°

• 0

• 1

• -1

• undefined

cos 180°

• 0

• 1

• -1

• undefined

sin 150°

• 1/2

• -1/2

• √3/2

• -√3/2

What are the coordinates of 60° on the unit circle?

• (0, 1)

• (1/2, √3/2)

• (√3/2, 1/2)

• (√2/2, 1/2)

We use the Unit Circle to construct the sine and the cosine functions. The unit circle is called the unit circle because:

• It is only one circle

• The area of the circle is equal to one

• Because its radius is equal to one

• Because its circumference is equal to one

cos(60°)

• 0

• 1/2

• √3/2

• 1