the remaining ruffled triangle long edge to the remaining t-shirt a long edge.
for a high-low hem fold t-shirt a in half, matching the side and shoulder seams; pin. measure and mark 1/2" below the lower ruffle. draw a line from the mark to the side seam lower edge (3). cut along the line through t shirt a only.
fold the t-shirt lower edges 1/2" toward the wrong side; press. pin, and then stitch using a stretch stitch or a narrow zigzag. 