Question: what is the formula to find the length of the apothem?
Answer: More Formulas We can also use the area formula to find the apothem if we know both the area and perimeter of a polygon. This is because we can solve for a in the formula, A = (1/2)aP, by multiplying both sides by 2 and dividing by P to get 2A / P = a. Here, the apothem has a length of 4.817 units.