This document provides instruction on calculating the circumference of a circle. It includes the formulas for circumference (C = πd and C = 2πr) and examples of using the formulas to find the circumference given the diameter or radius. It also includes examples of finding the radius or diameter given the circumference. The document is intended to teach students how to relate radius, diameter, and circumference and use formulas to solve for any one of those values if two values are known.

1. AIM: Circumference of a Circle
Do Now
1

2. Homework: 1.) Pages 432-433 #8-13 all, 26, 27
2.) PAges 436-437 #4-12 all, 22-25 all, 28-35 all
2

3. 3

4. Anticipatory Set:
Fill the What I Know and What I Want to Learn
sections of the following KWL Chart based on your
knowledge of finding the circumference of a circle.
What I Know What I Want to Learn What I Learned
4

5. QUESTION: What is the relationship between the
radius and diameter of a circle?
Circumference of a Circle Formulas
1.) C = πd
2.) C = 2πr
5

6. 1
Find the circumference of the following circle. Use the Pi
Button and round your final answers to the nearest
hundredth.
7y
d
6

7. 2
Find the circumference of the following circle. Use the Pi
Button and round your final answers to the nearest
hundredth.
cm
13
7

8. 3
A 153 m
B 306 m
C 76.5 m
D 151 m
Find the circumference and leave the answer in Pi notation.
Radius = 153 m
8

9. 4
A 2053 m
B 1026.5 m
C 4106 m
D 513.25 m
Find the circumference and leave the answer in Pi notation.
Diameter = 2053 m
9

10. QUESTION: Determine a method to find the radius or
diameter if you are given the circumference. Explain
your method.
Example: The circumference is 56 inches, what is the radius?
10

11. 5
If the circumference of a circle is 56 inches, find the
length of the radius and the diameter. Use the Pi Button
and round your final answers to the nearest tenth.
Radius = _____
11

12. 6
The circumference of the Superdome in New Orleans
is 2135.2 feet. Find the length of the radius and the
diameter of the Superdome. Use the Pi Button and
round your final answers to the nearest tenth.
Diameter = ______
12

13. 7
The circumference of a circle is 30π inches.
Find the radius and diameter.
Radius = _____
13

14. BEFORE YOU LEAVE
Go back to the KWL Chart in the
Anticipatory Set and fill in the What
I Learned section.
14

15. Mr. Tjersland's Math 7
Homework: Pages 426-427 #17-24 all, 33-41 all
15

16. AIM: Circumference of a Circle
Circumference of a Circle Formulas
1.) C = πd
2.) C = 2πr
Find the circumference of the following circle. Use the Pi
Button and round your final answers to the nearest
hundredth.
cm
13
16

17. AIM: Circumference of a Circle
Circumference of a Circle Formulas
1.) C = πd
2.) C = 2πr
If the circumference of a circle is 56 inches, find the
length of the radius and the diameter. Use the Pi Button
and round your final answers to the nearest tenth.
Radius = _____
17