The regular dodecagon has 12 sides. Each side has a length of x=9.25 cm, and we know that the perimeter of the figure is the sum of the lengths of all the sides: Therefore, since we have 12 sides, the perimeter will be given by the product between the length of each side, x, and the number of sides, 12:
First, lets figure out how many pencils we will need. so we can do that by 4 pencils x 28 children and we get 112. Then if there are 8 pencils in a package, we divide 112 by 8 and get 14