Circles - Calculating Area and Circumference

The Area of a Circle is calculated using this formula: [math]Area=\pi r^2[/math][br]The Circumference of a Circle is calculated using this formula: [math]Circumference=2\pi r[/math] or [math]Circumference=\pi d[/math][br][br]Important things to remember: [br][math]r=radius[/math][br][math]d=diameter[/math]
Circle
[br][size=100]The [color=#cc0000][b]red [/b][/color]line represents the diameter. The diameter is the distance of the widest part of the circle, from any point of the edge of the circle to the opposite side.[br][br]The [color=#6aa84f][b]green [/b][/color]line represents the radius (the distance from the centre of the circle to the outer edge).[/size]
– Mr E. Bissoon

Information: Circles - Calculating Area and Circumference