## Explanation

In geometry, the circumference of a circle with radius (r) is defined by the following formula: =2πr` `

The Greek letter π ("pi") represents the ratio of the circumference of a circle to its diameter. In Excel, π is represented in a formula with the PI function, which returns the number 3.14159265358979, accurate to 15 digits.

```
=PI() // returns 3.14159265358979
```

Therefore, the formula to calculate the circumference of a circle with a radius of 3 is:

```
=2*PI()*3 // returns 18.85
```

And the formula to calculate circumference based on the radius values in column B, is:

```
=2*PI()*B5
```