Go language program to calculate circle circumference

Following program shows you how to calculate circle circumference.
In this program we get circle radius from user and calculate circumference using following formula
Circumference = 2 X PI X r

package main

import "fmt"

func main() {

  var circleRadius float64
  var circumferenceOfCircle float64
  fmt.Println("Please enter the radius of circle:")
  fmt.Scanf("%f", &circleRadius)
  circumferenceOfCircle = 2 * 22/7 * circleRadius
  fmt.Println("Circumference of circle is: " , circumferenceOfCircle)
}

Output:

Please enter the radius of circle:
 9
Circumference of circle is:  54