# How Is Pi Used in Everyday Life?

**The number pi, represented by the symbol π, is used in everyday life to calculate the radius or circumference of circles and in design and construction.** Pi is an irrational number, often approximated to 3.14, that was discovered by Greek mathematicians as a ratio to relate the diameter of a circle to the circumference.

Pi is used for many different tasks in different professions and assists in different aspects of design work, particularly for round objects. Engineers who design things like tires, piping and tubing, round gaskets and balls use pi every day at work. For example, to determine the amount of material needed to make a basketball, designers used pi to figure out the surface area of a sphere of the appropriate size. Anytime a cylinder is made pi is used to determine the length required to wrap material all the way around it. Calculating the volume of a cylinder, cone or sphere also requires an operation of pi.

Many math-intensive professions regularly utilize pi, but it can also be used in daily non-professional life. When pi is used for in-home projects, often it is approximated at 3, whether calculated or simply visually estimated. If someone needs to coat a circular or cylindrical object, such as in painting a room or frosting a cake, they could use a rounded version of pi to determine about how much material is needed to completely coat the surface.