7.9B Explore 2- Calculate Circumference

Dropdown

Let's see what you remember from Explore 1: Circumference is the ​

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around the outside of a​

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​. Circumference is about ​

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times the​

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.

Labelling

Label what the variables in each equation represent.

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Circumference

diameter

radius

pi (3.14)

Categorize

Options (8)

Match the Pizza Circumference Cards to each size of Pizza, using the C= 2πr and C= πd equations.

Small Pizza

Medium Pizza

Large Pizza

Mega Pizza

Labelling

What do we already know about the small pizza based on the figure? Select the circumference equation based on the distance measured on pizza.

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8 in.

4 in.

C= 8π

C= 2π4

Math Response

What is the circumference for the small pizza?

Type answer here

Correct Answer: 25.12

Deg^°

Rad

Labelling

What do we already know about the medium pizza based on the figure? Select the circumference equation based on the distance given on pizza.

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C= 2π5

C= 10π

5 in.

10 in.

Math Response

What is the circumference for the medium pizza?

Type answer here

Correct Answer: 31.4

Deg^°

Rad

Labelling

What do we already know about the large pizza based on the figure? Select the circumference equation based on the distance given on pizza.

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C= 2π6

12 in.

6 in.

C= 12π

Math Response

What is the circumference for the large pizza?

Type answer here

Correct Answer: 37.68

Deg^°

Rad

Labelling

What do we already know about the mega pizza based on the figure? Select the circumference equation based on the distance given on pizza.

Drag labels to their correct position on the image

C= 2π8

16 in.

C= 16π

8 in.

Math Response

What is the circumference for the mega pizza?

Type answer here

Correct Answer: 50.24

Deg^°

Rad

Match

Check for Understanding: Match the following...

• What formula should be used to calculate the circumference if given the diameter?

• What formula should be used to calculate the circumference if given the radius?

• Pi (π)

C= πd

C=2πr

3.14

Diameter (d)

Radius (r)

• C= πd

• C=2πr

• 3.14

• Diameter (d)

• Radius (r)