Imperial units!
What is imperial units?
So what are imperial AND metric untis??
Imperial units: They are the old fashioned way of things like 1ft and 1mile ect they would or could all be converted into metric.
Metric units: They are a more new way of explaining grams ounce we occasionally use both but a few things are still in imperial units.
Here are a few that have been converted
1 sq foot (ft2) = 144 sq inches (in2)
1 sq yard (yd2) = 9 sq feet
1 acre = 4,840 sq yards
1 sq mile = 640 acres