Intro to the Unit Circle

What is the radius of the unit circle?

• 1

• 5

• 10

• It depends

Which point is the center of the unit circle?

• (0,0)

• (1,1)

• (0,1)

• (1,0)

Which coordinate relates to the sine of an angle?

• x-coordinate

• y-coordinate

• neither

Match the correct radian measure for letters a (30 degrees), b (45 degrees), and c (60 degrees) - what matching best completes Quadrant I of the Unit Circle with these Radian Measures?

• a

• 
• b

• 
• c

• 

What is this jawnski called?

What is the radius of a unit circle?

• 1

• 2

• 1/2

• 0

The unit circle has a radius length of...

• 0.5

• 1

• π

• 2π

What is the radius of the unit circle?

• 0

• 1

• 1/2

• √2/2

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

Match the following vocabulary related to the Unit Circle

• Pythagorean Identity

• the length of the curve formed by an arc

• radian measure

• measure of a central angle of a circle that intercepts an arc = in length to the r of that circle

• quadrantal angle

• the ratio of the arc length formed by an angle divided by the r of that circle

• radian

• an angle whose terminal sides lies on an axis

• arc length

• states that the square of the cosine of a given angle + the square of the sine of that angle = 1