3 7/16 is half of 6 7/8.
6 7/8 is half of 13 3/4.
I wasn't quite sure what you were asking.
6 7/8 half of?
6 7/8 is half of 2 × 6 7/8 or 12 14/8
= 13 6/8 or 13 3/4
Write 6 7/8 in simple fraction
6 7/8 = 55/8
1/2 of 55/8 = 55/8 × 1/2
= 55/4 = 13 3/4