Question

why do we need to have a leap year once every four years?

Answer 1

actually every year is 365 days and 6 hr so in 4 yrs 6 ×4 = 24hrs =1day therefore every four yrs an extra day adds as leap year

Answer 2

Answer:

because of the rotation of earth there are 365 days but every four years as 01 days as an extra during revolution.

so thus this condition we known as leap year.