Janelle is painting a spherical model of a human cell for a science fair. she uses 615.44 square inches of paint to evenly cover the outside of the cell with one coat of paint. what is the diameter of the cell model? (use 3.14 for the value of π.)

a-7 in.
b-8 in.
c-14 in.
d-16 in.

To solve for the surface area (SA) of the sphere given its diameter (d), the formula is 
 
                                          SA = πd^2

Manipulating the equation to solve for diameter, the equation becomes,
 
                                        d = sqrt (SA / π)

Substituting the value of surface area given and 3.14 for π
 
                                    d = sqrt (615.44 in^2 / 3.14) = 14 in

Therefore, the diameter of the cell model is 14 inches.