L2 Useful Rules About Angles - Part 1
Completion requirements
Unit A: Geometry
Chapter 1: Polygons
Other Useful Rules About Angles
Two more rules may be helpful in finding the measure of angles.
Rule 1: The angle of a straight line is 180°.
Consider what happens if the straight line is broken into several angles.
Knowing that a straight line has an angle measure of 180° means that .
Rule 2: A right angle is equal to 90°.
Similarly to the straight line, the angle can be made up of several angles that add up to 90°.
In this diagram, .