it has none
6 in.
d = 2r
100.53 inches
1.4 million kilometers (870,000 miles).
diameter = 128/pi
The name of half a diameter is a radius.
circumference = 15*pi cm
circumference = pi*40cm
Any value between 0 and 12 cm.
circumference = pi*diameter or pi = circumference/diameter
you have to measure the diameter of the coil and then multiply the diamter by pi