33 represents 100%. To find what percent represents 21, we can use the next proportion:
[tex]\frac{33}{21}=\frac{100\text{ \%}}{x\text{ \%}}[/tex]Solving for x:
[tex]\begin{gathered} 33\cdot x=21\cdot100 \\ x=\frac{2100}{33} \\ x=63.6\text{ \%} \end{gathered}[/tex]
