Knowing some basic geometric formulas may be very helpful in everyday life. A simple chart on the refrigerator door would be a ready reference for simple everyday situations. Basic Geometric formulas: Pi = 3.1416... Circumference of a Circle Circumference = pi x Diameter Area of a Circle Area = pi x Radius Squared Volume of a Cylinder Volume = Area x Height Perimeter of a Rectangle P = (2 x Length) + (2 x Height) Area of a Rectangle Area = Length x Width