How many yards of concrete in 214 square feet?

Answer 1

There is no sensible answer to this question. A square foot is a measure of area, with dimensions [L2]. A yard is a measure of distance, with dimensions [L]. In the context of concrete or other aggregate "a yard" is also used as an abbreviation for a cubic yard which is a measure of volume, with dimension [L3]. In either case the dimension is different to that of the area. Basic dimensional analysis teaches that you cannot convert between measures with different dimensions without additional information.