MHB What is the formula for finding the area of a circle?

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The discussion centers on finding the area of a circle using the formula A = πr². The user initially miscalculates the radius by incorrectly relating the diameter to the circumference. They clarify that the diameter is 10, not 10π, leading to the correct calculation of the radius as 5. The error in cubing π in the area calculation is acknowledged, emphasizing that the area should not involve volume. The thread concludes with the user recognizing their mistake and expressing gratitude for the correction.
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My Effort:

Circumference = pi•d

10 •pi = pi•d

10•pi/pi = d

10 = d, where d is the diameter of the circle.

Area = pi•r^2, where r is the radius of the circle.

Diameter = 2 times the radius.

10pi = 2r

10pi/2 = r

5pi = r

A = pi•r^2

A = pi(5pi)^2

A = 25•pi^3, which makes no sense.

Only the volume is cubed. This is not a volume question.
 
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mathland said:
Circumference = pi•d
10 •pi = pi•d
10•pi/pi = d
10 = d[/color], where d is the diameter of the circle. Correct![/color]
Area = pi•r^2, where r is the radius of the circle.
Diameter = 2 times the radius.
10pi[/color] = 2r Wrong![/color]
The diameter is 10, not 10pi.
 
Opalg said:
The diameter is 10, not 10pi.

I see my error. Thanks.
 
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