Merrie Rampy HIGHLAND SCHOOL, CRAIGMONT, ID
Algebra II : Unit #9 - Intro to Trig : Lesson #3

Objective: SWBAT use radians interchangeably with degrees when working with a unit circle.
Standards: HSF-TF.A.1 HSF-TF.A.2 MP1 MP2 MP4 MP6
Subject(s): Math
60 minutes
1 Set the Stage - 7 minutes
2 Put it into Action - 40 minutes

You will need copies of the Measuring Radians handout.  You will  also need two pieces of string per team (one between 40cm and 70cm and the other approximately 4 times as long), a piece of chalk and a meter stick for each team. I put the string and chalk in a baggie so that each team has the correct combination of string lengths.  It is much more interesting if the shorter strings are NOT all the same length so that each team gets different data.

Team Work (15-20 min): This activity requires each team of students to have an area at least three meters square, so if your room does not accommodate that, I suggest moving to a carpeted hallway or a paved area outside.

For this activity I have students work in teams of 2-3, but you can use as many as 4 per group.  If you have more than 2 students per team, I suggest assigning specific tasks to each student to encourage participation and accountability. Possible tasks include recorder, measurer, timekeeper, materials manager, or reporter.  Give each team member a copy of the handout entitled “Measuring radians”.  I allow approximately 2 minutes for the teams to read through the handout and develop their plan for successfully completing the activity. (MP1, MP4)  When the teams have completed reading the handout I ask if there are any questions then have the materials manager collect the tools for his/her team.   At this point I either move the class to the area we will be working, or designate areas within my classroom for each team and assign them a team number for completing the class data chart. If we are working somewhere other than my classroom I tell students that they will be recording their data to the board when we return to class.

If we remain in the classroom, while teams are drawing their circles and beginning to make their radii measurements I draw a chart on the board as shown in the resource labeled “Class data”.  If we leave the classroom I either post the chart before we leave or have it ready to project when we return.