Download Part I: Parts of a Circle

Date: _____________________
Student: _______________________
Shape & Space: Understanding Circles
Outcome: SS7.1 Demonstrate an understanding of circles, including circumference and central
angles.
Additional Materials:
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Geometry set
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String
Part I: Parts of a Circle
1) Define each of the following.
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Circumference –
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Diameter –
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Radius –
2) Use your compass to draw a circle with a diameter of 8 cm. Label each of the following.
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Circumference
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Diameter
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Radius
Date: _____________________
Student: _______________________
3) Use your compass to make a circle with a radius of 5 cm.
4) Fill in the blank.
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The smaller the circumference, the smaller the _______________.
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To create a larger circumference, it is best to change the size of the _______________.
5) True or false.
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A circle with a small circumference will rotate more than a circle with a larger
circumference.
True
False
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The diameter of a circle is half the length of the radius.
True
False
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A compass draws a circle by adjusting the size of the radius.
True
False
Date: _____________________
Student: _______________________
Parts Two: Central Angles of Circles
1) What is a central angle? How is one made?
2) Use your compass to draw a circle below.
Divide the circle into four central angles.
Measure each of them and record their totals.
3) True or False – The total of a circle’s central angles is 300 degrees.
4) Does the size of the circle change the total sum of the central angles?
Date: _____________________
Student: _______________________
Part Three: Relationship between Radius and Diameter
1. Finish this statement:
o The diameter of a circle is ____________ the radius.
2. Calculate the diameters of the circles using the following radii.
a. 4 cm
b. 7 cm
c. 13 cm
3. Calculate the radii for the circles using the following diameters.
a. 2 cm
b. 5 cm
c. 8 cm
Date: _____________________
Student: _______________________
Part Four: Circumference and Diameter – Irrational Numbers – Pi
1) Explain how you would find the circumference of a circular object.
2) What is Pi? How is it calculated?
3) What is the value of Pi?
4) Explain why Pi is useful when working with circles.
5) Fill in the chart below. Calculate the missing measurements by using the correct formula
that uses Pi. Show your work.
Radius
Diameter
Circumference
3 cm
9 cm
10 cm
15 cm
10 cm
4 cm