What is the formula for finding the distance around a circle?

Answer 1

Finding the distance around a circle is simple. The distance around a circle is called the circumference. To find the circumference, you must do the following: Diameter x pi. It can also be written as 2 x pi(3.14) x Radius.
The distance around a circle is called the circumference. To find the circumference, you multiply Pi by diameter. Another way to find it is 2 times 3.14 times radius. 2x3.1.4xr.
The distance around a circle---it's circumference---or the length of some portion thereof---a segment---is measured in linear distance units such as inches, centimeters, feet, or meters.

The portion of a circle (the relative distance around) that a segment represents---the segment's circular arc---is measured in units of angular magnitude. In basic geometry and lay usage, the most common angular unit is the degree. In scientific and higher math usage, the most common unit is the radian. The circumference of a circle has an arc of 360° (360 degrees), or 2π rad (2 × pi radians). A radian therefore is equivalent to 180/π degrees. Other units of angular magnitude include the turn (360° or 2π rad), grad (aka gon; 1/400 turn), quadrant (1/4 turn), arcminute (1/60°), and arcsecond (1/60 arcminute).


The length of a segment---the distance along it---can be determined according to any of the following formulas, where:

L represents the length of the segment,
θ the circular arc in radians,
⍺ the circular arc in degrees,
r the radius of the circle,
C the circumference of the circle;

If you know the radius and need the total circumference:
C = 2 × π × r

If you know the radius and arc, and need the segment length, one of:
L = θ × r
L = (⍺ × π × r) / 180

If you know the circumference and arc, and need the segment length, one of:
L = (θ × C) / (2 × π)
L = (⍺ / 360) × C

The circular arc of a segment can be determined according to any of these formulas;

If you know the radius and length, one of:
θ = L / r
⍺ = (180 × L) / (π × r)

If you know the circumference and length, one of:
θ = (2 × π × L) / C
⍺ = (360 × L) / C

The circumference of (distance around a) circle is equal to the diameter times pi. It is also equal to 2 x pi x radius.

Answer 2

The distance around a circle is called the circumference. To find the circumference, you multiply Pi by diameter. Another way to find it is 2 times 3.14 times radius. 2x3.1.4xr.

Answer 3

The circumference of (distance around a) circle is equal to the diameter times pi. It is also equal to 2 x pi x radius.