If each of the three pieces glued together constitute a frame, then each frame is (6.5" + 6.5" + 6.5") in perimeter, or 19.5" total when all three sides added together. If you convert that to yards, then each frame is
1yard / 36inches = x yards / 19.5 inches, solve for x by multiplying both sides by 19.5
x = 0.5416 yards
If you have 2 yards total divide by 0.5416 yards required to cover one frame, and
2/ 0.5416 = 3.6923 frames
So you'd be able to cover 3 frames with ribbon.