Area Perimeter Formulas. Area of a circle A p r 2 p4 D 2 07854 D 2 Circumference of a circle C 2 p r p D. Other times it means the length of that line as in the circumference is 211cm.
Given the radius of a circle the circumference or perimeter can be calculated using the formula bwloe.
You find the area of a semicircle by plugging the given radius of the semicircle into the area of a semicircle formula. For a polygon the perimeter is the sum of its side lengths. The formula for the area A A of a circle is built around its radius. Formula for Circumference of a Circle r Radius of the circle D Diameter C Circumference of a circle p 314.