Because, if the year is divisible by 400, then it is a leap year.
The years divided by 100 are not leap years unless these are divisible by 400. So 19th century has only 24 leap years but 21st century has 25 as year 2000 was a leap year.
24. Although there are 100 years in a century, and a leap year is normally every 4 years, and 100 divided by 4 is 25, the year 2300, which is the last year of the 23rd century is not a leap year, due to the rules for leap years. It is divisible by 100, but not by 400.
in 4th century B.C. it was the year 400 B.C. and ended in 301 B.C.
400 to 499
[1 January] 301 to [31 December] 400.
0.05
2012 was the third leap year in the 21st century. The 21st century started in 2001, not in 2000 as some people believe, so 2004 was the first leap year, 2008 was the second leap year and 2012 was the third leap year.
In one century there are 36,524 days. However, years that can be divided by 100 but not 400 are not leap years. Therefore, one century out of four will actually have 36,525 days.
0.0136
85.25
41
7