Go Arithmetic Operators calculate circle area and circumference

package main/*from  w w w .j  a  v  a2 s  .  c  o  m*/

import "fmt"

func main(){
    var rad float64
    const PI float64 = 3.14 // Constant
    var area float64
    var ci float64
    fmt.Print("Enter radius of Circle : ")
    fmt.Scanln(&rad)
    area = PI * rad * rad 
    fmt.Println("Area of Circle is : ",area)
    ci = 2 * PI * rad
    fmt.Println("Circumference of Circle is : ",ci)     
}