MATH 2360Q Lecture Notes - Lecture 7: Protractor, Contraposition
Document Summary
We"ll now introduce our last undefined term: angle measure. For every angle bac, there is a real number ( bac) called the measure of bac such that the following conditions are satisfied: 0 ( bac) < 180 for every angle bac. Angle construction postulate: for each real number r with 0 < r < 180, and for each half-plane h bounded by ab, there exists a unique ray ae such that e is in h and ( bae)= r . Angle addition postulate: if the ray ad is between rays ab and ac, then. Once again, we don"t care how we measure angles, just that we can. We can apply some familiar terms from high school geometry to the setting. Two angles bac and edf are congruent if ( bac)= ( . An acute angle is ( bac) < 90 . An obtuse angle if ( bac) > 90 .
