When a point is rotated about the x axis the new point is at an equal distance from the point of rotation.
The given Urn (red) is rotated along the line x=1 .The rotated points will be at equal distance from the line x=1.In the figure the blue Urn is the rotated figure about the line x=1.
The coordinates of the points are mentioned in the diagram attached .In the rotated figire the y values remains same while for x coordinateis of the point at the same disstane from line x=1 .