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A team in science class placed a chalk mark on the side of a wheel and rolled the wheel in a straight line until the chalk mark returned to the same position. The team then measured the distance the wheel had rolled and found it to be 25 cm. To the nearest tenth, what is the area of the wheel?

A) 99.5 cm2

B) 19.6 cm2

C) 49.7 cm2

D) 198.9 cm2

Respuesta :

sqdancefan

Answer:

  C)  49.7 cm²

Step-by-step explanation:

You want the area of a wheel with a circumference of 25 cm.

Area

A formula for the area of a circle that can be used here is ...

  A = C²/(4π) . . . . . . . where C is the circumference of the circle

  A = (25 cm)²/(4π) ≈ 49.7 cm² . . . . . matches choice C

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Additional comment

The area formula used most often is A=πr². When r=C/(2π), this becomes ...

  A = π(C/(2π))² = πC²/(4π²) = C²/(4π)

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