Circle Math Cheat Sheet (and Worksheet

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To re-build or customize your cheat sheet (table below) hit the Randomize button. You could also enter the values manually (for Radius or Diameter) directly on the table. Just click on them to place the cursor there and change them to suit your needs.

[Worksheet]

[Printer friendly]

Circle Math

d = 2r
C = 2πr
A = πr²

Radius	=
Diameter	=	8.00
Circumference	=	25.13
Area	=	50.27

Diameter	=
Radius	=	38.00
Circumference	=	238.76
Area	=	4536.46

Radius	=
Diameter	=	46.00
Circumference	=	144.51
Area	=	1661.90

Diameter	=
Radius	=	20.00
Circumference	=	125.66
Area	=	1256.64

Radius	=
Diameter	=	50.00
Circumference	=	157.08
Area	=	1963.50

Diameter	=
Radius	=	30.00
Circumference	=	188.50
Area	=	2827.43

Radius	=
Diameter	=	64.00
Circumference	=	201.06
Area	=	3216.99

Diameter	=
Radius	=	34.00
Circumference	=	213.63
Area	=	3631.68

Radius	=
Diameter	=	26.00
Circumference	=	81.68
Area	=	530.93

Diameter	=
Radius	=	11.00
Circumference	=	69.12
Area	=	380.13

Radius	=
Diameter	=	52.00
Circumference	=	163.36
Area	=	2123.72

Diameter	=
Radius	=	31.00
Circumference	=	194.78
Area	=	3019.07

Radius	=
Diameter	=	32.00
Circumference	=	100.53
Area	=	804.25

Diameter	=
Radius	=	36.00
Circumference	=	226.19
Area	=	4071.50

Radius	=
Diameter	=	20.00
Circumference	=	62.83
Area	=	314.16

Diameter	=
Radius	=	15.00
Circumference	=	94.25
Area	=	706.86

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Exporting the Cheat Sheet to PDF

To export the cheat sheet as a PDF, you can follow these simple steps that leverage the browser's capabilities to save the printer-friendly version of the sheet as a PDF:

Click on the Printer friendly link (here or above the table), or on the Worksheet link if you wanted to get the Worksheet instead of the Cheat Sheet.
Press Ctrl + P (or Cmd + P on Mac) to open the print dialog
In the print dialog, choose Save as PDF as the destination.

The specific steps may vary slightly depending on the browser being used. This enables you to create a portable and accessible version of the cheat sheet that you can refer to anytime, anywhere.

About Circle Math

A circle is a set of points in a plane that are equidistant from a fixed point called the center. The distance from the center to any point on the circle is called the radius (denoted as r).

Radius (r): The distance from the center of the circle to any point on its boundary.
Diameter (d): The distance across the circle through its center, equal to twice the radius.
Formula: d = 2r
Pi (π): A mathematical constant approximately equal to 3.14159. It is the ratio of the circumference to the diameter of any circle.
Circumference (C): The distance around the boundary of the circle, essentially the perimeter of the circle.
Formula: C = 2πr or C = πd
Area (A): It measures the amount of space inside the circle. It's closely related to the radius and is calculated using the mathematical constant Pi. The units of area are always square units (e.g., cm², m²).
Formula: A = πr² or A = π(d/2)²