Understanding Sector Area of a Circle

This video tutorial explains how to calculate the area of a sector, also known as a pizza slice, using degrees. It provides two examples: one with a 60° angle and a radius of 8, and another with a 45° angle and a diameter of 20. The tutorial walks through the process of using the formula for sector area, reducing fractions, and calculating the final area in terms of pi.

What is the formula used to calculate the area of a sector?

• Measure over 180 times pi times radius squared

• Measure over 360 times pi times diameter squared

• Measure over 360 times pi times radius squared

• Measure over 180 times pi times diameter squared

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CCSS.4.G.A.1

In the first example, what is the measure of the angle given?

• 30°

• 90°

• 60°

• 45°

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CCSS.7.G.B.4

What is the radius of the circle in the first example?

• 12

• 8

• 6

• 10

How is the fraction 60/360 simplified in the first example?

• 1/6

• 1/4

• 1/8

• 1/10

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CCSS.HSG.C.B.5

What is the final area of the sector in the first example?

• 48π/3

• 32π/3

• 64π/3

• 16π/3

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CCSS.4.G.A.1

In the second example, what is the measure of the angle?

• 30°

• 60°

• 45°

• 90°

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CCSS.7.G.B.4

What is the diameter of the circle in the second example?

• 10

• 20

• 15

• 25

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CCSS.7.G.B.4

How is the radius determined from the diameter in the second example?

• Radius is one-third of the diameter

• Radius is equal to the diameter

• Radius is half of the diameter

• Radius is double the diameter

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CCSS.4.MD.C.5B

CCSS.HSG.CO.A.1

What is the simplified fraction of the angle measure in the second example?

• 1/10

• 1/4

• 1/8

• 1/6

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CCSS.HSG.C.B.5

What is the final area of the sector in the second example?

• 75π/2

• 25π/2

• 50π/2

• 100π/2

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CCSS.HSG.C.B.5