Understanding Reference Angles

The video tutorial explains how to find reference angles, which are angles between 0 and 90 degrees or 0 and π/2 radians, formed between the terminal ray of an angle and the x-axis. It covers examples using both degrees and radians, including positive and negative angles. The tutorial also discusses the congruence of triangles formed by reference angles and provides formulas for calculating reference angles in different quadrants.

What is the range of a reference angle?

• 90 to 180 degrees

• 0 to 360 degrees

• 0 to 180 degrees

• 0 to 90 degrees

Tags

CCSS.5.G.A.1

Why is it important to always drop a perpendicular to the x-axis?

• To ensure the reference angle is positive

• To find the angle with the y-axis

• To make the angle negative

• To find the angle with the origin

How do you determine the reference angle for a 300-degree angle?

• By adding 300 to 90

• By subtracting 300 from 180

• By adding 60 to 300

• By subtracting 300 from 360

Tags

CCSS.8.G.A.2

What is the significance of congruent triangles in reference angles?

• They have different side lengths

• They are not related to the unit circle

• They have the same side lengths and angles

• They are only used in radians

Tags

CCSS.8.G.A.2

How do you find the reference angle for 2π/3 radians?

• Subtract 2π/3 from π

• Add π to 2π/3

• Divide 2π/3 by π

• Multiply 2π/3 by 2

Which formula is used to find the reference angle in the second quadrant?

• 180 - θ

• θ

• 360 - θ

• θ - 180

What is the reference angle for an angle in the third quadrant?

• θ

• 180 - θ

• θ - 180

• 360 - θ

What is the reference angle for an angle in the fourth quadrant?

• θ

• 180 - θ

• θ - 180

• 360 - θ

What is the reference angle for a negative angle of -210 degrees?

• 210 degrees

• 150 degrees

• 330 degrees

• 30 degrees

In which direction do you move for a negative angle?

• Clockwise

• Counterclockwise

• Upwards

• Downwards