molarity of acetic acid = vol. of base x molar concentration of the base, placed over, vol. of the acid = ? (mole)

molarity of sodium hydroxide = 1 mole
volume of vinegar weighed = 20ml
vol. of the vinegar titrated = 87ml
molecular weight of acetic acid = 60g
weight of vinegar sample = 19.26g

titration result = beginning buret vol., 62ml
                   ending buret vol., 25ml
                   volume added, 87ml