Using the surface area of the sphere, it is found that the radius of the bearing that Helen needs to buy is of 6 millimeters.

What is the surface area of a sphere?

The surface area of a sphere of radius r is given by:

[tex]S_A = 4\pi r^2[/tex]

In this problem, we have that:

[tex]S_A = 452.16[/tex]

Hence:

[tex]4\pi r^2 = 452.16[/tex]

[tex]r = \sqrt{\frac{452.16}{4\pi}}[/tex]

r = 6.

The radius of the bearing that Helen needs to buy is of 6 millimeters.

More can be learned about the surface area of a sphere at