To find Diameter:

Multiply circumference by

0.3183

Or divide circumference by

3.1416

To find Radius:

Multiply circumference by

0.15915

Or divide circumference by

6.28318

To find the Side of an inscribed Square:

Multiply diameter by	0.7071	x	x
Or multiply circumference by	0.2251	Or divide the circumference by	4.4428

To find the Side of an Equal Square:

Multiply diameter	0.8862	Or divide diameter by	1.1284
Or multiply circumference by	0.2821	Or divide circumference by	3.545

Square:

A side multiplied by	1.4142	equals diameter of it's circumscribing circle.
A side multiplied by	4.443	equals circumference of its circumscribing circle.
A side multiplied by	1.128	equals diameter of an equal circle.
A side multiplied by	3.547	equals circumference of an equal circle.
Square inches multiplied by	1.273	equals circle inches of an equal circle.

To find Area of a Circle:

Multiply circumference by one-quarter of the diameter.	b
Or multiply the square of diameter by	0.7854
Or multiply the square of circumference by	0.07958
Or multiply the square of 1/2 diameter by	3.1416

To find the Surface of a Sphere or Globe:

Multiply the diameter by the circumference	g
Or multiply the square of the diameter by	3.1416
Or multiply four times the square of the radius by	3.1416