====== Radians and Degrees ====== ===== Definitions ===== ==== Standard Position ==== An angle is in standard position if the initial side of the angle is on the x-axis between the 1st and 4th quarter. ==== Positive Angle ==== An angle that extends counterclockwise((a common misconception is that angles are positive when rotated clockwise, the standard in mathematics is the opposite)). ==== Negative Angle ==== An angle that extends clockwise. ==== Coterminal Angle ==== Equivalent angle that has a different numerical value. Add or subtract $360$ for degrees and $2\pi$ for radians to get a coterminal angle. ===== Degrees ===== Degrees is an angle measurement where one full revolution is 360. ==== Degrees Minutes Seconds ==== Instead of a decimal representation, degrees can also be specified in minutes and seconds, akin to standard time((which supposedly degrees are [[https://en.wikipedia.org/wiki/Degree_(angle)#History|based on]])). The conversion to decimal is $x + \frac{y}{60} + \frac{z}{3600}$ where x is whole unit degrees, y is minutes((denoted by ' mark/foot mark)), and z is seconds((denoted by " mark/inches mark)). ===== Radians ===== A radian is a measurable length where the radius of a circle equals to an arc length section of the circle. $r = s$ where $r$ is the radius and $s$ is the arc length segment. {{:math:2021-01-06-081544_1107x572_scrot.png?400|}} ===== Converting Rad to Deg and vice versa ===== The conversion is $\pi = 180$ degrees. Degree to **Radian**: $d * \frac{\pi}{180} = r$ Radian to **Degree**: $r * \frac{180}{\pi} = d$ ===== Complementary and Supplementary Angles ===== * Angles are complementary when they sum up to 90° or $\frac{\pi}{2}$ * Angles are supplementary when they sum up to 180° or $\pi$