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