The diameter of a circle is 0.31831 times the circumference; the circumference is 3.1416 times the diameter; the area (external surface) is the diameter multiplied by itself (squared) and by 0.7854; the diameter multiplied by 0.8862 equals the side of a square of the same area; the side of a square multiplied by 1.128 equals the diameter of a circle of the same area; the diameter multiplied by the circumference equals the surface of a globe.