The video tutorial explains how to determine reference angles for given angles. It covers the concept of reference angles, which are acute angles formed by the terminal side of a given angle and the x-axis. The tutorial provides three examples: 221 degrees, 347 degrees, and -125 degrees, demonstrating how to calculate the reference angle for each. Reference angles are important for constructing reference triangles and determining trigonometric function values.

What is a reference angle?

• An angle that is always 90 degrees.

• The acute angle formed by the terminal side of a given angle and the x-axis.

• An angle that is always less than 45 degrees.

• The angle formed by the initial side and the terminal side of a given angle.

How do you sketch an angle in standard position?

• By rotating the angle clockwise from the x-axis.

• By drawing the angle starting from the y-axis.

• By placing the initial side on the x-axis and rotating counterclockwise.

• By drawing the angle starting from the origin.

What is the reference angle for a 221-degree angle?

• 139 degrees

• 221 degrees

• 41 degrees

• 59 degrees

Tags

CCSS.8.G.A.5

Why are reference angles important?

• They are used to find the area of a triangle.

• They help in determining the length of the hypotenuse.

• They allow us to use special reference triangles to find trigonometric values.

• They are used to measure the height of a triangle.

What is the reference angle for a 347-degree angle?

• 23 degrees

• 47 degrees

• 77 degrees

• 13 degrees

How do you find the reference angle for an angle greater than 180 degrees?

• Subtract the angle from 360 degrees.

• Divide the angle by 2.

• Subtract 180 degrees from the angle.

• Add 180 degrees to the angle.

What is the reference angle for a -125-degree angle?

• 55 degrees

• 125 degrees

• 35 degrees

• 90 degrees

How do you find the reference angle for a negative angle?

• Add 360 degrees to the angle.

• Take the absolute value of the angle.

• Add 180 degrees to the angle.

• Subtract the angle from 180 degrees.

Tags

CCSS.5.G.A.1

What is the significance of sketching a perpendicular from the x-axis to the terminal side?

• It helps in finding the length of the terminal side.

• It is used to construct the reference triangle.

• It determines the initial side of the angle.

• It measures the angle of rotation.

What is the reference angle if the terminal side is 35 degrees past the -y axis?

• 145 degrees

• 125 degrees

• 55 degrees

• 35 degrees