Question

What is the approximate surface area of the sphere if circumference is 37.68?

Answer 1

The surface area of a sphere is  A = 4 π R² .

Sadly, the question doesn't give you 'R', so you have to
back it out of the circumference.

                           Circumference = π (diameter)

Divide each side by π :  Diameter = circumference / π

Radius = 1/2 diameter:  Radius = circumference / (2 π)

                                       Area = 4 π R²  =

                                                 4 π (circumference/2π)² =

                                                 4 π (circumference)² / 4 π²

Divide top and bottom by  4π :  Area = (Circumference)² / π

         Circumference = 37.68 units

         Area =  (37.68)² square units /π =
    
                       451.93 square units