A pr2 2 A p r 2 2. As the polygon gets to look more and more like a circle the value approaches the circle circumference which is 2pr. Area p x r 2 in terms of radius r.
While its a good idea to memorize these formulas here is a list of perimeter circumference and surface area formulas to use as a handy reference.
It is most important topic in the Maths for classes 6 and 7 as well as upper. So substituting 2pr for ns. Here radius of circle r angle between two radii is th in degrees. While its a good idea to memorize these formulas here is a list of perimeter circumference and surface area formulas to use as a handy reference.