+1667 The circumference of a circle is found using the formula pi*r^2.
Let me give an example.
Let's say a circle has an radius (r) of 3. If no radius is provided, but a diameter is, you have just divide the diameter by 2 since the diameter is 2 times the radius.
Anyways, the radius is 3, so first we must do 3^2, which is 9.
Now we have pi*9.
Next, multiply 9 by pi (which is approximately 3.14159265358979323...)
In this example, I multiplied by 3.14.
9*3.14=28.26
In conclusion, the circumference of a circle with a radius of 3 is approximately 28.26.
