hello am trying to see if am doing this right

Given an expression below
[tex]\begin{gathered} \frac{p}{81}\text{ = 11} \\ \text{cross multiply} \\ \frac{p}{81}=\text{ }\frac{11}{1} \\ p\text{ }\times1\text{= 11 }\times\text{ 81} \\ p\text{ = 891} \end{gathered}[/tex]Then the expresion will be equal once the value of p = 891
Hence the value of p = 891