Reference Angles and Triangles in the Unit Circle

What are the coordinates of the point on the unit circle corresponding to an angle of 45 degrees?

• (1, 0)

• (0.5, 0.5)

• (0, 1)

• (0.707, 0.707)

What is the sine of the angle 30 degrees in the unit circle?

• 0

• 2

• 0.5

• 1

Find the reference angle for an angle of 210 degrees in the unit circle.

• 210

• 180

• 150

• 30

Solve the equation sin(x) = 0.5 using the unit circle.

• 60 degrees or π/3 radians

• 45 degrees or π/4 radians

• 30 degrees or π/6 radians

• 90 degrees or π/2 radians

Graph the function y = cos(x) using the unit circle.

• The graph of y = cos(x) using the unit circle is a wave-like curve that oscillates between -1 and 1.

• The graph of y = cos(x) using the unit circle is a constant value of 1.

• The graph of y = cos(x) using the unit circle is a parabola.

• The graph of y = cos(x) using the unit circle is a straight line.

What are the coordinates of the point on the unit circle corresponding to an angle of 60 degrees?

• (0.866, 0.5)

• (0.5, 0.866)

• (0.5, 0.5)

• (0.866, -0.5)

What is the cosine of the angle 45 degrees in the unit circle?

• 1

• 0

• 1/sqrt(2)

• sqrt(2)

Find the reference angle for an angle of 300 degrees in the unit circle.

• 60 degrees

• 30 degrees

• 45 degrees

• 90 degrees

Solve the equation cos(x) = -0.8 using the unit circle.

• -143.13 degrees or -2.498 radians

• 143.13 degrees or 2.498 radians

• 36.87 degrees or 0.644 radians

• 90 degrees or 1.571 radians

Graph the function y = sin(x) using the unit circle.

• The graph of y = sin(x) using the unit circle is a wave-like curve that oscillates between -1 and 1 as x varies.

• The graph of y = sin(x) using the unit circle is a constant function.

• The graph of y = sin(x) using the unit circle is a parabola.

• The graph of y = sin(x) using the unit circle is a straight line.