# import necessary libraries
import pandas as pd

# define your series
my_series = pd.Series([10,20,30,40,50,60,70,80,90])

# use quantile() pandas method
percentile_25 = my_series.quantile(0.25)
percentile_75 = my_series.quantile(0.75)

# print results
print(f'25th Percentile is: {percentile_25}')
print(f'75th Percentile is: {percentile_75}')