Understanding the Unit Circle

What is the radius of the unit circle?

• π

• 0

• 1

• 2

On the unit circle, what does the y-coordinate of a point represent?

• Sine of the angle

• Cosine of the angle

• Radius of the circle

• Tangent of the angle

How is the angle 90° represented in radians?

• 2π

• 3π/2

• π

• π/2

Which of the following is a multiple of 30°?

• 45°

• 60°

• 90°

• 120°

In a 30-60-90 triangle on the unit circle, what is the length of the side opposite the 30° angle?

• 2

• √3/2

• 1

• 1/2

When a 30-60-90 triangle is flipped into the third quadrant, what happens to the coordinates?

• Both coordinates become positive

• Both coordinates become negative

• Only x becomes negative

• Only y becomes negative

What is the cosine of a 45° angle on the unit circle?

• √3/2

• 0

• √2/2

• 1

What is the coordinate of the point at 0° on the unit circle?

• (0, -1)

• (1, 0)

• (0, 1)

• (-1, 0)

Which quadrant has both x and y coordinates negative?

• First

• Second

• Fourth

• Third

What is the sine of 210° on the unit circle?

• 1/2

• √3/2

• -1/2

• -√3/2