wheel diameter times pi times number of rotations
circumference of a circle = pi*diameter or 2*pi*radius
If the circumference or diameter is given then you can find the radius or simply measure the distance from the centre of the circle to the circumference.
First find the circumference of the whole circle using Pi x diameter. Halve the answer and add the diameter. Thus: 3.1416 × 10 = 31.416 ÷ 2 + 10 = 25.708cm So the perimeter of the semi-circle is 25.7cm
Multiply 22/7 by the diameter of the circle. Or 3.14
Divide the distance traveled by the product of the diameter and pi.
wheel diameter times pi times number of rotations
Divide the Diameter by 2 to get the Radius
Diameter = circumference/pi
To find the distance around the circle, you must find the diameter, which is two times the radius. Then you multiply the length of the diameter by Pi. (Pi is a constant roughly equal to 3.14).
Pi x diameter
Diameter = circle's circumference/pi
multiply the diameter times pi (3.14159265)
If: circumference = pi*diameter Then: pi = circumference/diameter
Multiply the diameter by the constant pi.
The radius of a circle is the distance from the center to an outside edge of the circle. The diameter is the distance all the way across the circle. Therefore, the radius is half the value of the diameter.
EDIT: To find the diameter, using the circumference - you divide the circumference by the value of Pi - Snakester1962 (Supervisor)