What has the same relationship to circle : cylinder?

Circle is a plane figure ( flat , 2-dimensional)

meanwhile, cylinder is a solid figure ( 3-dimensional, can be filled with volume)

They both have the same relationship because in order to build a cylinder , you need two circles ( at the top and the bottom), and the size of that circles will directly affected the cylinder's volume

The charge of an ion with 55 protons and 52 electrons is +3. the reason is because protons are positive, and there are three more than the amount of negative electrons.