If pressure(P) is inversely proportional to volume (V) then     1)  $\text{PV}=\text{constant}$2)    $\text{V}\alpha \frac{\text{1}}{\text{P}}$ 3)     ${\text{P}}_{\text{1}}{\text{V}}_{\text{1}}={\text{P}}_{\text{2}}{\text{V}}_{\text{2}}$ 4)  $\frac{\text{P}}{\text{V}}=\text{constant}$