What is formula to convert diameter to perimeter?

Answer 1

The perimeter P is the distance around a given two-dimensional object. The word perimeter is a Greek root meaning measure around, or literally "around measure". P = pi times d d = diameter The circumference C is the distance around a closed curve. Circumference is a kind of perimeter. C = pi times d d = diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle. In more modern usage, the length of a diameter is also called the diameter. In this sense one speaks of "the" diameter rather than "a" diameter, because all diameters of a circle have the same length, this being twice the radius. Conversion perimeter C to diameter d and back: C = pi times d d = C / pi

Answer 2

Given the diameter (D) and the number of sides (n) of a regular polygon, the perimeter (P) is:

P = Dn * sin(π / n)

When using the formula for circumference (C), assume the circle has a number of sides that approaches infinity;

C = Dn * sin(π / n), as n -> Infinity