166 arms (178-12) of the sea lily were not damaged. This is 93.26% of the total number of arms.
Percent means “for every 100” or "out of 100." The (%) symbol as a quick way to write a fraction with a denominator of 100. As an example, instead of saying "it rained 14 days out of every 100," we say "it rained 14% of the time."
Formula for calculating percentages
The formula for calculating percentages or for converting from percentages are relatively simple.
Use this free online Percentage Calculator tool to calculate percentages.
See examples of percentage calculations at mathsisfun.com.