2012 Common Core State Standards Summer Institute
Using perimeter and circumference- “Whose line is it anyways?”
1. Students will determine which straight lines represent the perimeter or circumference
of given polygons and circles.
Teacher will ask students if they have ever helped build a fence around his or her yard or
if they have ever ran on a track. Teacher should ask how they knew how much fence was
needed or how far did they run?
Teacher and students brainstorm about how they solve real world problems and how
they use math to accomplish these tasks.
Teacher should assess prior knowledge at this point:
What do you call the distance around shapes, or polygons?
How do you calculate this distance around shapes, or polygons?
Are there special formulas to calculate this distance?
Teacher demonstrates the vocabulary of the lesson. The teacher will need to ensure that
students understand the concept of perimeter, circumference, radius, diameter, arc, and
Teacher explains the process of calculating the perimeter of various shapes or polygons.
The teacher needs to explain that the circumference of a circle could be seen as the
perimeter of the circle. At this point, teacher should illustrate the circumference
formula and the formula for finding arc length. To help illustrate circumference,
teacher can link robotics to this topic explaining that circumference can help illustrate
how far a robot can travel with round wheels.
Students work on the robotics worksheet calculating all of the missing information by
following the steps on the worksheet. These calculations can be completed in small
groups for the first condition and the second condition can be completed individually.
Students will explain how they solved for the missing information on the robotics
worksheet. Students can explain how their answer may have changed if there had been
different information on the worksheet.
Students will be challenged to create their own math/CTE examples of where they may
find circumference or arc length at work in the real-world. (Excluding examples given in