6.1 Angles and Their Measure θ: the Greek letter theta, which is used as a variable for angle measurement. degree (°): 1/180 of a straight angle minute(‘): 1/60 of a degree second(“): 1/60 of a minute DMS: the use of degrees, minutes, and seconds as opposed to decimal degree measure.

Converting Between DMS And Decimal To convert to DMS, take the decimal part of the angle and multiply by 60. The new whole number is the minutes, multiply the new decimal part by 60 to get the seconds. To convert from DMS, divide minutes by 60 and seconds by 3600 and add fractions to the whole number of degrees.

Example 1: Converting to DMS Convert 23.235° to DMS.

Example 2: Converting from DMS Convert 13° 12’ 54” to decimal notation.

What is a Radian??? radian: the angle measure of a central angle where the radius and arc length are the same.

Angle Conversions To convert radians to degrees, multiply by To convert degrees to radians, multiply by

Example 3: Angle Conversion Convert 34° to radians.

Example 4: Angle Conversion convert to degrees

Arc Length Radian Measure: Degree Measure: r = radius of circle

Example 5: Arc Length Find the perimeter of a 60° slice of a 12in. diameter pizza.

6.1 HW Assignment Pg. 365 #s 24-58 evens, 72-78 evens