1. It is common knowledge that there are 365 days in a calendar year. However, 365 days is an approximation: the earth actually takes 365 days, five hours, 48 minutes, and 46 seconds to go around the Sun once in its orbit. What is the latter length of time called?
2. Over four years or so, the additional five hours, 48 minutes, and 46 seconds accumulate to become an additional day, which the calendar accounts for by adding an extra day. This is the leap day, today, February 29. What are days added to calendars to keep the latter in step with a natural phenomenon called?
3. In the Gregorian calendar, a leap day is added to the month of February every four years, as long as the year is divisible by 100 but not by 400. This is why, for example, 2000 was a leap year but 1800 was not. In the ______ calendar, a leap day is added every four years without skipping any. Fill in the blank.
