I JUST LOVE DOING BLOGS ON MY SUNDAYS

7-1

I'm going to be reteaching lesson 1 of chapter 7 where we learn how to convert between degrees and radians, and how to find co-terminal angles.

• When working with degrees, you often get a decimal answer. When you get a decimal, you are usually told to convert to minutes(') and seconds("). To convert to minutes, you take what's following the decimal, and multiply it by 60. To convert to seconds, you take what is following the decimal in your answer for minutes, and multiply it by 60.
• To convert minutes and seconds to degrees, you do the following: (degree + min/60 + sec/3600)
• To convert from degrees to radians, you do the following: (degree x pi/180)
• To convert from radians to degrees, you do the following: (radians x 180/pi) *pi cancels out
• To find a co-terminal angle in degrees, you do the following: (+/- 360)
• To find a co-terminal angle in radians, you do the following: (+/- 2pi(n))

Example 1: Convert 16.33 degrees to degrees/min/sec.

-.33 x 60 = 19.8'

-.8 x 60 = 48"

= 16 degrees, 19', 48"

Example 2: Convert 60 degrees to radians.

-60 degrees x pi/180 = pi/3

Example 3: Convert 3pi/4 to degrees.

-3pi/4 x 180/pi = 135 degrees

Example 4: Find a co-terminal angle to pi/4.

-pi/4 + 2pi = 9/4pi