Donald G. Ryder, Ph.D., 84, died at home. He was an Eagle Scout, in the Naval Air Corps during World War II, a self employed airplane crop duster pilot, a college baseball coach, a professor of mathematics, an author, a member of the Society of Mayflower Descendents and the American Legion. He is survived by sons, Art and Rick, six grandchildren, and two great-grandchildren. A private ceremony will be held. Arrangements are in the care of Whitfield Funeral Home, North Chapel, Demorest, Georgia.