Find the co-terminal angles and calculate the principal measure of a given angle.
After completing this tutorial, you will be able to complete the following:
Co-terminal Angles and Principal Measure
Angles in standard position that have the same terminal ray are called co-terminal angles.
Angles measuring between 0 and 360 degrees, or between 0 and radians are called principal angles.
An angle has several co-terminal angles. The measure of the one co-terminal angle whose measure is between 0 and 360 degrees, or between 0 and radians, is called the principal measure of that angle.
We can write co-terminal angles in terms of their principal measure:
Finding the Principal Measure
To find the principal measure of a given angle, learners should try to write it in the form of either or .
Determining the k value here could be a little tricky. For the angles given in degrees, dividing the measure of the angle by 360 using the regular long division method could be very helpful. Quotient will give the k value, and remainder will give the principal measure.
The following other key vocabulary terms will be used throughout this Activity Object:
|Approximate Time||25 Minutes|
|Pre-requisite Concepts||angle concepts, degree, radian|
|Type of Tutorial||Concept Development|
|Key Vocabulary||co-terminal, co-terminal angles, principal angle|