Question

why there are 29 days in feb in leap year?

Answer 1

 a popular legend, July was named after Julius Caesar and hence it had 31 days. Later, when Augustus Caesar took over the Roman Empire, he wanted August, the month named after him, to have 31 days as well. Hence, the two extra days were taken from February, which was then left with 28 days. However, some historians don't agree with this reasoning. They believe February always had 28 days ever since the time of King Numa Pompilius. He decided that a year would have 355 days, the length of 12 lunar cycles. Back then, even numbers were considered unlucky. So, he created seven months with 29 days, and four with 31. Since he now needed one short even-numbered month, he chose February, as it was considered the least favourite month for it arrived during the middle of winter. And hence, it was given only 28 days

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Answer 2

the earth takes 365 days 5 hours 48 minutes and 56 seconds to complete one revolution around the sun. to make it convenient we count only 365 days in a year. the balance of about 6 years added up to 24 hours or 1 day after every 4 years. so that's why the leap year has 1 extra day.