First substitute 9 for l and 5 for w in the expression $\displaystyle{l}\cdot{w}\usepackage{cmbright}\Huge\$ and then multiply: $\displaystyle{9}\cdot{5}={45}\usepackage{cmbright}\Huge\$ . Next substitute 7 for l and 7 for w in the expression and then multiply: $\displaystyle{7}\cdot{7}={49}\usepackage{cmbright}\Huge\$ . The larger floor area is 49.