2 3/4a=19 1/4
÷2 3/4 ÷2 3/4
a=1/7
3 Metres; because for each 100 centimetres there is one metre. With centi- being the prefix for 10^-2 in the metric system.
Unit rate means how much does it cost for 1 unit
140 for 18ft^2
divide by 18
140/18=7.77777777777777
so the unit rate is $7.78 per square foot
