Katherine Marie Johnson and Samuel John Kristoff announce their engagement. Parents of the couple are Rick and Lori Johnson of Marshall and Joe and Deb Kristoff of Marshall. The couple are 2006 graduates of Marshall High School and 2010 graduates of the University of Minnesota. Kristoff plans to begin employment as an applications engineer for National Instruments in Austin, Texas, in July. The couple plans a May 28, 2010, wedding at Como Park in St. Paul and will move to Texas in July.