Circle Graphs
Vocabulary
Circle Graph  graph that represents data as part of a circle. The entire circle represents all of the data.
Objectives
This lesson will teach students how to interpret, create, and display data in a circle graph. Students will be exposed to mulitple uses and applications of circle graphs.
 The students will be able to interpret data displayed in a circle graph.
 The students will create a circle graph to display data.
Lesson Essential Question(s)
 In what situations can circle graphs be used to display different groups of data?
 When should I use a circle graph?
Duration
One Class Period
Materials
 Compass
 Rulers
 Protractors
 Pizza boxes
 Paper
 Graphing Calculators
 http://illuminations.nctm.org/ActivityDetail.aspx?id=60 "Circle Grapher" Illuminations. Thinkfinity.org. Web. 3 Mar, 2010. http://www.thinkfinity.org/.
 Circle Graphs.doc
Suggested Instructional Strategies
This lesson is designed to promote active engagement through the use of auditory, kinesthetic, nonlinguistic representation, and visual spatial opportunities. Explicit instruction, differentiated instruction, and inquirybased instruction will be used to further the mastery of the concepts presented.
Instructional Procedures
WHERETO 

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The teacher will review circle graphs with the students. She/he will remind the students that circle graphs show data as parts of a whole. The circle represents the whole, or total. The segments represent the parts. She/he will also explain that the data in a circle graph can be shown as fractions or percents. The sum of the fractions is always 1 and the sum of the percents is always 100. The teacher will also explain that because circle graphs resemble a pie cut into slices, they are sometimes referred to as pie graphs or pie charts. The teacher will ask the students to name a few situations that may require a circle graph (examples family budgets, percentage of time students study for each academic subject, or how a student spends a typical day). This application activity will serve as a formative assessment to determine student understanding of when circle graphs can be used. Based on student responses, the teacher will reteach/review as necessary. 
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The teacher will tell the students that they are going to create a circle graph to display the favorite type of pizza in the class. The teacher will survey the students cheese, pepperoni, sausage, and supreme. The survey results will be organized into a table or list. 
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The teacher will use illuminations “Circle Grapher” http://illuminations.nctm.org/ActivityDetail.aspx?id=60 to help the students interpret data found in a circle graph. The students will practice converting data into percents. Teacher monitoring will be used as a formative assessment to gauge student understanding. The teacher will guide the students through the process of making a circle graph. The teacher will assist the students in converting their data into percents.
# of people selecting a type 2. Next, the students will convert the fractions into decimals and percents. The teacher will tell the students that in order to find the size of the section required for each type of pizza on their circle graph, they must first calculate the angle measure for each type. The teacher will review how to find the percent of number. She/he will tell the students that they will be finding the percent of 360 degrees, the total number of degrees in a circle. The students will use calculators to calculate the angle measures for each section of the graph.

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The students will be divided into groups. Each group will be given a pizza box. Inside the pizza box will be a blank piece of paper, protractor, and a compass. The teacher will guide the students through the process of using the compass to create a perfect circle on the paper. The teacher will then tell the students to start at the center of the circle and draw a radius to the outside of the circle. She/he will then have the students place their protractor on the circle so that the 90 degrees is directly above the center of the circle. The students will then draw each angle that they calculated above. She/he will explain to the students that each time they add a new section to the circle graph the radius changes to the line they just drew.

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Upon completion of the group graph, the students will be given an independent worksheet Circle Graphs.doc to complete. This worksheet will have the students create their own graph and interpret data in their graph.

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Cooperative learning and calculators will be used to assist the students with this lesson. Ongoing student monitoring (formative assessment) will allow the teacher to adapt instruction to meet individual student needs. This corrective feedback will allow students to obtain mastery of the concepts. Because this lesson utlizes various methodologies including tactile, kinesthetic, visual, cooperative learning and real world application, many student learning styles will be addressed. The following website will provide reteaching/extra practice for students: http://www.pdesas.org/module/content/resources/3165/view.ashx 
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The students will be provided with an extension activity. Students needing enrichment will be given a graphic calculator and asked to create a circle graph on a graphing calculator. 
Formative Assessment
Formative assessments via informal observation will allow the teacher to make adjustments based on individual student needs. Teachers will gauge student learning through observation of task completion and provide additional opportunities for enrichment or remediation/reteaching as necessary.
Related Materials & Resources
Website to provide extra practice/reteaching: http://www.pdesas.org/module/content/resources/3165/view.ashx