Exploring Cosine of 120 Degrees and the Unit Circle

What is the cosine of an angle greater than 90 degrees defined as in the unit circle?

• The y-value of the point formed by the angle

• The x-value of the point formed by the angle

• The tangent of the angle

• The secant of the angle

What is the first step in finding the cosine of an angle greater than 90 degrees?

• Draw the angle in the unit circle

• Calculate the sine of the angle

• Identify the reference angle

• Memorize the cosine values

What does the x-value of the point formed by the angle in the unit circle represent?

• The tangent of the angle

• The cosine of the angle

• The sine of the angle

• The cotangent of the angle

What is the reference angle used to find the cosine of 120 degrees?

• 30 degrees

• 45 degrees

• 60 degrees

• 90 degrees

What is the cosine of 60 degrees, which is used to find the length of the blue side in the triangle?

• 0

• sqrt(2)/2

• 1/2

• 1

How is the cosine of the reference angle related to the cosine of 120 degrees?

• It is the positive inverse

• It is the negative inverse

• It is the same

• It is the negative of the cosine of the reference angle

Why is the cosine of 120 degrees negative?

• Because it is in the fourth quadrant

• Because it is in the third quadrant

• Because it is in the second quadrant

• Because it is in the first quadrant

What is the importance of finding a reference angle in trigonometry?

• To determine the correct sign of the trigonometric functions

• To calculate the area of the circle

• To simplify complex calculations

• To find the hypotenuse of the triangle

What does the reference angle represent in the context of the unit circle?

• The smallest angle at which the line intersects the circle

• The angle between the x-axis and the line

• The angle between the line and the point of intersection with the circle

• The angle from the x-axis to the line forming the angle in question

In which quadrant is the point formed by 120 degrees located?

• Fourth Quadrant

• Third Quadrant

• Second Quadrant

• First Quadrant