Hi Anne,
If you knew the length (L), width (W) and thickness (T), all expressed in yards, then the volume of concrete in the patio would be
L W T cubic yards.
You know the volume is 2 cubic yards and hence
L W T = 2 cubic yards.
The thickness is 4 inches and there are 12 inches in a foot so 4 inches is ^{4}/_{12}= ^{1}/_{3} of a foot. There are 3 feet in a yard so ^{1}/_{3} of a foot is ^{1}/_{3} ^{1}/_{3} = ^{1}/_{9} of a yard. Hence
L W ^{1}/_{9} = 2 cubic yards
and thus
L W = 18 square yards.
Penny
