As with finding distances on a number line, the easiest way is to subtract the smaller coordinate from the larger. Here, the "number line" is the arc at the edge of the protractor. The corresponding coordinates are ...
S: 40°
R: 70°
Q: 100°
P: 160°
The measure of an angle with its vertex at V will be the difference between the "coordinates" of the endpoints of the arc it intercepts. That is ...
