Open Up - Grade 7 - Mathematics - Unit 3 - Lesson 8

The picture shows a circle divided into 8 equal wedges which are rearranged. The radius of the circle is r and its circumference is 2𝜋r . How does the picture help to explain why the area of the circle is 𝜋r2?

A circle’s circumference is approximately 76 cm. Estimate the radius of the circle.

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7.G.4

A circle’s circumference is approximately 76 cm. Estimate the diameter of the circle.

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7.G.4

A circle’s circumference is approximately 76 cm. Estimate the area of the circle.

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7.G.4

Jada paints a circular table that has a diameter of 37 inches. What is the area of the table?

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7.G.4

The Carousel on the National Mall has 4 rings of horses. Kiran is riding on the inner ring, which has a radius of 9 feet. Mai is riding on the outer ring, which is 8 feet farther out from the center than the inner ring is.In one rotation of the carousel, how much farther does Mai travel than Kiran?(Round to the nearest tenth)

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7.G.4

The Carousel on the National Mall has 4 rings of horses. Kiran is riding on the inner ring, which has a radius of 9 feet. Mai is riding on the outer ring, which is 8 feet farther out from the center than the inner ring is.One rotation of the carousel takes 12 seconds. How much faster does Mai travel than Kiran?(Round to the nearest tenth)

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7.G.4

Here are the diameters of four coins: A coin rolls a distance of 33 cm in 5 rotations. Which coin is it?(round to the nearest tenth)

• Penny
• Nickel
• Dime
• Quarter

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7.G.4

Here are the diameters of four coins: A quarter makes 8 rotations. How far did it roll?(round to the nearest tenth)

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7.G.4

Here are the diameters of four coins: A dime rolls 41.8 cm. How many rotations did it make?(round to the nearest whole number)

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7.G.4