Lesson 1.6 – Measuring Angles
Good definitions are very important in geometry!! In this lesson you will learn how to write a good
definition.
Which figure is a polyglob? ___________
Once you’ve written a definition you should test it by trying to find a counterexample. If you can find a
counterexample, then you don’t have a good definition.
Beginning Steps to Creating a good Definition:
1. Classify your term. What is it? (“A square is a 4-sided figure…”)
2. Differentiate your term. How does it differ from the others in that class? (“…that has four
congruent sides and four right angles.”)
3. Test your definition by looking for a counterexample.
Defining Angles:
An angle is: __________________________________________________
Congruent Angles are: _________________________________________
Right Angle:_______________________________________________________________________________
Acute Angle: ______________________________________________________________________________
Obtuse Angle: _____________________________________________________________________________
Complimentary Angles: _____________________________________________________________________
Supplementary Angles: _____________________________________________________________________