March 29 2009 was 90 days after December 29 2008.
Counting from December 1, 2011, adding 90 days to this date gives February 29, 2012.
Adding 90 days to September 30, 2010 gives December 29, 2010.
91 days including February 29; 90 days without it
Adding 90 days to August 29 gives November 27.
90 days after December 1st is Tuesday, March 1, 2011.
Adding 90 days to March 29, 2011 gives June 27, 2011.
What date is 90 days before December 25 2012
Adding 90 days to December 23, 2010 gives March 23, 2011.
90 days after Tuesday, December 28, 2010 = Monday, March 28, 2011.
Adding 90 days to November 29 of any year gives February 27 of the following year.
The date which falls 90 days after December 4, 2010 is March 4, 2011.
90 days in equivalent to 3 months.