Hello, Truthbetold!

Find an equation of the largest sphere contained in the cube

determined by the planes: .

Are these planes the boundaries of the sphere with the distance being the diameter?

Yes!

You don't need the Distance Formula . . . just some visualization.

. . And they said it was a, didn't they?cube

Can you see that the radius of the sphere is 2 ?

The center of the sphere must be halfway between the planes.

The center is and the radius is 2.

Go for it!