Question

If the area of a circle is 58 square feet, find the circumference. A. 42.5 ft. B. 4.25 ft. C. 22.35 ft. D. 26.99 ft.

Answer 1

Answer: OPTION D.

Step-by-step explanation:

The formula for calculate the circumference of a circle is:

$C=2r\pi$

Where r is the radius.

The formula for calculate the area of a circle is:

$A=r^2\pi$

Where r is the radius.

Solve for r from $A=r^2\pi$ to calculate it:

$r=\sqrt{\frac{A}{\pi}}\\r=\sqrt{\frac{58ft^2}{\pi}}\\r=4.296ft$

Subsitute the radius into $C=2r\pi$. Then:

$C=(2)(4.296ft)\pi=26.99ft$

Answer 2

Answer:

D. 26.99 ft

Step-by-step explanation:

The formula for area of a circle is

A = πr², where r is the radius. We are given A = 58, so plug that in to find r...

58 = πr²    solve for r...

   58/π = r²           (divide both sides by π)

       √(58/π) = r       (take the square root of both sides)

now simplify...

           (√58)/(√π) = r

               [(√58)(√π)]/[(√π)(√π)] = r

                       [√(58π)]/π = r  

The formula for circumference is C = 2πr,  where r is the radius....so we have

  C = 2π([√(58π)]/π)      now simplify...

        C = 2√(58π)             (the 2 pi's cancel out)

          C = 26.9972124    (crunch in your calculator)