The 31st of May 2011.
Adding 180 days to December 30, 2010, gives June 28, 2011.
Adding 180 days to December 13, 2010 gives June 11, 2011.
Adding 180 days to December 18, 2010 gives June 16, 2011.
To find the date 180 days before July 28, 2010, you can subtract 180 days from that date. This calculation leads to January 30, 2010. Therefore, 180 days before July 28, 2010, is January 30, 2010.
September 1, 2010 + 180 days = February 28, 2011.
October 13, 2010 + 180 days = April 11, 2011.
Adding 180 days to February 3, 2010 gives August 2, 2010.
Adding 180 days to February 8, 2010 gives August 7, 2010.
Adding 180 days to August 10, 2010 gives February 6, 2011.
Adding 180 days to November 23, 2010 gives May 22, 2011.
Adding 180 days to August 13, 2010 gives February 9, 2011.
Adding 180 days to October 9, 2010 gives April 7, 2011.