The Concept of Angles

Degrees may also be divided into minutes and seconds, though such a division is not as universal as it once was. Sometimes, parts of a degree will be referred to decimally. For example, seven and a half degrees will be written as 7.5degrees. Each minute is then divided into 60 equal parts called seconds. Thus, seven and a half degrees may be called as 7 degrees and 30 minutes, and written 7 30'

A third means of measurement include that of radian for which the unit circle will be considered. The angle cuts off the arc of the circle, and the length of that arc will be the radian measure of the angle. To convert between degree measurement and radian measurement, consider 2pi as 360degrees. Thus, 1 degree equals pi/180radians, and 1radian equals 180/pidegrees