Mr. and Mrs. William Cauthen of Leesburg, Fla., announce the engagement of their daughter Miss Mandy Sara Cauthen to Mr. John Knox Burns IV, son of Dr. and Mrs. John Asbury Burns of Gainesville. The bride-elect is a 2003 graduate of Leesburg High School in Leesburg, Fla. She graduated in 2007 from Auburn University with a bachelor’s degree in environmental design.