Why not make the whole set of Pentagon balls? They are great for the little ones to play with and could each be made from different sets of fabrics.
They are fun and quick to make and not as difficult as you may think.
The pattern pack contains detailed instructions for all 3 ball sizes, including:
The Toy Ball 1 Trio pattern gives balls of these approximate sizes:
Note: The pattern pack DOES NOT contain any fabric or toy stuffing.