The Unit Circle Quiz

Which expression can be used to determine the reference angle for an angle, x, measuring 150°?

180 degrees - x

The radius of the circle below intersects the unit circle at (3/5, 4/5). What is the approximate value of thea?

53.1 degrees

Which of the following best explains why cos 2pie/3 cannot equal cos 5pie/3 ?

NOT A or B

What is the value of cos thea in the diagram below?

Not 4/3

Which of the following explains why cos 60 = sin 30 using the unit circle?

The side opposite a 30° angle is the same as the side adjacent to a 60° angle in a right triangle. On a unit circle, the y (sin) distance of a 30° angle is the same as the x (cos) distance of a 60° angle.

Which equation can be used to determine the reference angle, r, if thea = 7pie/12?

r=pie - thea

What is the value of tan thea in the unit circle below?

sqrt 3/3

On the unit circle, where 0<thea<=2pie, when is tan thea undefined?

thea = pie/2 and thea = 3pie/2

Which of the following is true of the location of the terminal side of an angle, thea, whose sine value is 1/2?

thea has a reference angle of 30° and is in Quadrant I or II

Which of the following is true of the values of x and y in the diagram below?

y/x=1