How do I work out the questioner at the bottom of the table? I have to show work and also want to double check the answers

Volume of NaOH Consumed 17.23 ml 17.31ml 17.39ml Calculated Molarity of Acetic Acid in the Vinegar Sample 0.87M 0.87M 0.87M Volume NaOH Consumed at Midpoint Reading 8.66 ml 8.7 ml Moles of NaOH Consumed at Midpoint Reading [A-] 0.04398M 0.044M Moles of Acetic Acid Remaining at Midpoint [HA] .01759M 0.174M Calculated pK. 4.289 4.316 Average calculated molarity of acetic acid 0.87M Average acetic acid concentration expressed in percent by mass _17.4ml Average value of pK. of acetic acid based on provided experimental data 4.3 Percent error for pK. of acetic acid _7.9%