I have a floor 17'8"×9'9" I know the sq ft but the lunolium is sold by sq yard and I can't fig out what it is

You are going to need an 6 yds x 4 yds piece. There are 3 feet in a yard. If you are looking a roll stock you would need a 4 yd width to cover.

Divide square feet by 9 for yardage but it is sold in 12' widths so you will have waste or have to seam it. Tiles may be cheaper, you will nead 180 plus a few extras to be safe.

What width does the sheet vinyl you want come in? Many are 12', the heavy duty ones come only 6' wide.

So, if 12' wide, you buy 12x18" or 24 sq. yds.
If it's 6' wide 6x29'3" plus 2 pattern matches. Could be 31-33' or 20.67 to 22 sq. yds.

Generally, sheet goods are better than vinyl tiles.

Jaz