How to do it...

1. Open the console and create the folder chapter03/recipe04.
2. Navigate to the directory.
3. Create the main.go file with the following content:

        package main

        import (
          "fmt"
          "math/big"
        )

        const PI = `3.1415926535897932384626433832795028841971693
                    993751058209749445923078164062862089986280348253
                    421170679821480865132823066470938446095505822317
                    253594081284811174502841027019385211055596446229
                    4895493038196`
        const diameter = 3.0
        const precision = 400

        func main() {

          pi, _ := new(big.Float).SetPrec(precision).SetString(PI)
          d := new(big.Float).SetPrec(precision).SetFloat64(diameter)

          circumference := new(big.Float).Mul(pi, d)
 
          pi64, _ := pi.Float64()
          fmt.Printf("Circumference big.Float = %.400f\n",
                     circumference)
          fmt.Printf("Circumference float64 = %.400f\n", pi64*diameter)

          sum := new(big.Float).Add(pi, pi)
          fmt.Printf("Sum = %.400f\n", sum)

          diff := new(big.Float).Sub(pi, pi)
          fmt.Printf("Diff = %.400f\n", diff)

          quo := new(big.Float).Quo(pi, pi)
          fmt.Printf("Quocient = %.400f\n", quo)

        }

1. Execute the code by running go run main.go in the Terminal.
2. You will see the following output: