Find the reference angle for each angle.
4.7

Key Concepts

Reference Angle

The reference angle is the acute angle formed by the terminal side of a given angle and the x-axis. It is always measured as a positive angle and is crucial for simplifying trigonometric calculations. For angles greater than 180 degrees, the reference angle is found by subtracting 180 degrees from the angle, while for angles in the fourth quadrant, it is calculated by subtracting the angle from 360 degrees.

Quadrants of the Coordinate Plane

The coordinate plane is divided into four quadrants, each representing a different range of angles. Quadrant I contains angles from 0 to 90 degrees, Quadrant II from 90 to 180 degrees, Quadrant III from 180 to 270 degrees, and Quadrant IV from 270 to 360 degrees. Understanding which quadrant an angle lies in is essential for determining its reference angle and the signs of its trigonometric functions.

Angle Measurement

Angles can be measured in degrees or radians, with 360 degrees equivalent to 2π radians. In trigonometry, it is important to be able to convert between these two units to accurately find reference angles. For example, an angle of 4.7 radians can be converted to degrees to better understand its position in the coordinate plane and subsequently find its reference angle.