The Earth takes approximately 365.25 days to revolve around the Sun. To account for the time beyond 365 days, we add a
day to the calendar

It takes approximately 365.25 days for Earth to orbit the Sun — a solar year. We usually round the days in a calendar year to 365. To make up for the missing partial day, we add one day to our calendar approximately every four years. That is a leap year.

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