It depends on the particular design.
I don't know what a "4 black telescope" is. You'd have to be more specific and at least give a manufacturer and model number.
It depends on the type of reflecting telescope.
1:Single Vision Lenses 2:Multi focal Lenses 3:Bifocal Lenses 4:Progressive lenses Source Vision Express India
4
1 3/4
4 x 4 x 2 = 32 cubic inches.
54 4x4-inch tiles.
6 x 12 + 4 = 76
4 quarters
4 of them.
1/4 inch is 6.35mm
Obviously 4.