โญ Circle Area Calculator
Calculate area and circumference of a circle from its radius.
What is a Circle?
A circle is the set of all points in a plane equidistant from a fixed point called the center.
How to Calculate Area
Area Formula
S: Area | r: Radius | ฯ โ 3.14159...
radius ร radius ร pi
How to Calculate Circumference
L: Circumference | D: Diameter (D = 2r)
radius ร 2 ร pi = diameter ร pi
Pi (ฯ)
The ratio of a circleโs circumference to its diameter. Approximately 3.14159265..., an irrational number with infinite non-repeating decimals.
Archimedes and Circle Area
Ancient mathematician Archimedes used inscribed and circumscribed polygons to compare perimeters and calculate ฯ with remarkable accuracy.
Newton's Infinite Series for ฯ
Isaac Newton devised a method to compute ฯ more precisely using infinite series. Advances in mathematics have since extended ฯ to billions of digits.
March 14 is Pi Day (ฯ Day)
Every year, March 14 is celebrated as โPi Dayโ, originating from the value 3.14. Pi plays a central role in mathematics, physics, engineering and beyond.