Solution: Take OF⊥CD as the point and the intersection with AB as E, connecting OA and OC. Because ab∑CD, OE⊥AB, according to the vertical diameter theorem, AE = 1/2ab = 15, CF = 1/2cd = 8. In RT△OCF, the solution of OF= 15 is obtained according to Pythagorean theorem, and since AB and CD are on the same side, the distance between AB and CD is OF-OE=EF= 15-8=7.