Respuesta :

DeanR

Still begging?  OK.  Let's do it with algebra first then put in the numbers.

We're given the Circumference of a circle C, and we want the area A.

The radius is related to the circumference by

C = 2π r

The area is related to the radius by

A = π r²

Solving for r in the first equation,

r = C/(2π)

So the area is

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

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OK we're given C=25 1/7 inches, π≈22/7

C = (7×25 + 1)/7 = 176/7 = (22×8)/7

That's a little convenient.

A = C²/4π = ( (22×8)/7 )² / (4 (22/7) ) = (8²/4) (22/7) = (16*22)/7 = 352/7

After those nice numbers they want an approximation.  How disappointing.

A = 50.2857142857 sq inches

Answer: 50.29