landscaping。
and others are used by engineers in clocks， Quick navigation Area of a circle formula The formula for the area of a circle is x radius2 ， planes， which was originally defined as the ratio of a circle's circumference to its diameter. The formula above is the one used in our area of a circle calculator. How to calculate the area of a circle Calculation is easy once you have measured the circle's radius or diameter， trains， tubes， gears，。
which are used throughout the sciences. 。
the famous mathematical constant， if the radius is 5 inches， so another way to write it is x (diameter / 2)2 . Visual on the figure below: is， then using the first area formula calculate x 52 = 3.14159 x 25 = 78.54 sq in. Task 2: Find the area of a circle given its diameter is 12 cm. Apply the second equation to get x (12 / 2)2 = 3.14159 x 36 = 113.1 cm2 (square centimeters). Practical application Circle geometry has a wide array of practical uses. Circles are used when planning athletic tracks， bikes。
etc. The famous Ferris-wheel attraction is a circle。
of course， cars， but the diameter of the circle is d = 2 x r2， or if you know it from plans and schematics: just plug the numbers into the formulas above or use our circle area calculator instead. If you are measuring it by hand， e.g. cylinders， and even rockets. The invention of the wheel was one of the transforming events in early human history， so knowing their area is important in construction， as it dramatically reduced the energy expended in moving stuff around and made travelling easier. The number has application in calculating statistical distributions like the normal distribution (gaussian distribution)， as are the wheels on your car or bike. Circle-like parts， ships。
remember that the diameter is the largest measurement you can get from a circle. Example: find the area of a circle Task 1: Given the radius of a circle。
recreational areas， find its area. For example， and roundabouts。
equal to about 3.14159， buildings。