This is the beginning of TRIGONOMETRY!!!  Don't worry, it's not all that difficul.  This is the section where you get all of the background information for the next 4 sections.  In this section you learn about revolutions (not like the French, but as in 360 degrees), minutes, seconds, standard positions, degrees, quadrantal angles, radian measures, and coterminal angles.  You will also learn how to use trigonometry to find the approximate size of an object if all you have is its apparent size.  This is a short section, but the next four sections will build upon it.