Math 4 fun: Circle equations formulas and calculator

Monday, November 15, 2010

Circle equations formulas and calculator

If you have one unknown variable:

circumference (c)

area (A)

radius (r)

or diameter of the circle (d)

just type it in the calculator below. Other values will be calculated quickly using the following formulas:

$r=\frac{d}{2}=\frac{c}{2\pi}=\sqrt{\frac{A}{\pi}}$
$d=2r=\frac{c}{\pi}=2\sqrt{\frac{A}{\pi}}$
$c=2r\pi=d\pi=2\sqrt{A\pi}$
$A=r^2\pi=\frac{d^2\pi}{4}=\frac{c^2 }{4\pi}$

where π is calculated to 10 significant digits.

$\pi=3.1415926536$

Name	Label	Value
Radius	r
Diameter	d
Circumference	c
Area	A

Yabba dabba do :)

1 comment:

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