one acre is equivalent to 43,560 square feet. if an acre is also equivalent to 4,840 square yards, how many square feet are equal to one square yard?

You don't need the acre conversions for this. You know that three feet = one yard, expressed as . If you square this (one square foot is literally one foot squared, the same goes for yards), then , which means , so there are nine square feet in a square yard.