In an arithmetic sequence, the consecutive terms differ by a common difference. This means that the second term minus the first term would be equal to the third term minus the second term. The pattern continues.
Looking at the sequence, the common difference is
3 3/4 - 4 = 3 1/2 - 33/4 3 1/4 - 3 1/2 = - 1/4
The next term after 3 1/4 would be 3 1/4 + - 1/4 = 3 1/4 - 1/4 = 3
The next term after 3 would be 3 + -
