$140 ÷ 18 = $7.7777
rounded = $7.78 per square foot
NOT SURE WHAT YOUR QUESTION WAS EXACTLY SO GAVE YOU SOME OPTIONS
or $140 for 18ft² = $140 for 324ft
or $140 ÷ 324ft = $0.43 per foot
$140 ÷ 18 = $7.7777
rounded = $7.78 per square foot
NOT SURE WHAT YOUR QUESTION WAS EXACTLY SO GAVE YOU SOME OPTIONS
or $140 for 18ft² = $140 for 324ft
or $140 ÷ 324ft = $0.43 per foot