You know the basic proportion:
[tex]\frac{P}{100}=\frac{A}{B}[/tex]
Where "P" is percent, "A" is the amount and "B" is the base.
You need to find the percent of 21 that represents 7. Let be "P" this percent you must find.
In this case, you can identify that:
[tex]\begin{gathered} A=7 \\ B=21 \end{gathered}[/tex]
Then, substituting values and solving for "P", you get:
[tex]\begin{gathered} \frac{P}{100}=\frac{7}{21} \\ \\ P=(\frac{7}{21})(100) \end{gathered}[/tex][tex]P\approx33.3[/tex]
Hence, the answer is: 33.3% (approximately)
