How do you find the area of a circle? Can you measure the area of a circle and use that to find a value for Pi?

Learn about the definition of pi in relation to a circle with this BBC Bitesize Maths article. For students between the ages of 11 and 14.

Why is the area of a circle proportional to the square of its radius? And why is that ratio the same as the ratio of the circumference to the diameter?

What Is a Circle? My favorite way to define a circle is in terms of how to draw one. In the episode What Is Pi? we learned how to draw a circle arts-and-crafts style. To do this, start by cutting ...

Pi is useful for more than finding the area and circumference of a circle. It turns up in all kinds of places, pretty much in any calculation that involves curves. Pi is used in fields from ...

Letter Published: 02 April 1914 A Triangle that gives the Area and Circumference of any Circle, and the Diameter of a Circle equal in Area to any given Square G. B. MATHEWS Nature 93, 110 (1914 ...