7-1

Since we've been doing trig review I'm gonna go over 7-1. This section is about converting degrees to radians, radians to degrees, and how to find co-terminal angles.

When you are converting from degrees to radians you use the formula degrees*pi/180

When you are converting from radians to degrees you use the formula radians*180/pi

When you convert from radians to degrees and you have to find minutes, you take what's behind the decimal and multiply it by 60. If you have to find seconds then you use what's behind the decimal after you find minutes and multiply it by 60. If there is a decimal, just drop what's behind it.

To convert back to degrees, you use this formula: degrees+min/60+sec/3600

To find a co-terminal angle, you add or subtract 360 if in degrees, or add or subtract 2pi if in radians.

example 1:

Convert 200 degrees to radians

200*pi/180

10 pi/9

example 2:

convert 5 pi/9 to degrees

5 pi/9 * 180/ pi

the pis cancel

100 degrees