trying to find the equations to use to Calculate the Sharpe ratio for each portfolio

Calculate the Sharpe ratio for each portfolio and compare their performance 1 2 Average return Return standard deviation Sharpe Ratio 3 Portfolio 1 9.50% 13.50% 4 Portfolio 2 5.50% 2.25% 5 Portfolio 3 12.50% 15.00% 5 7 Risk-free return 4.00% 8 9 Which is the best portfolio