pythag.go

package main

import "fmt"
import "math"

var pow = math.Pow
var sqrt = math.Sqrt

func main() {
	x1, y1 := 0, 0
	x2, y2 := 4, 5

	a := float64(x2 - x1)
	b := float64(y2 - y1)
	c2 := pow(a, 2.0) + pow(b, 2.0)

	fmt.Println(sqrt(c2))
}

pythag2.go

package main

import "fmt"
import . "math"

func main() {
	x1, y1 := 0, 0
	x2, y2 := 4, 5

	a := float64(x2 - x1)
	b := float64(y2 - y1)
	c2 := Pow(a, 2.0) + Pow(b, 2.0)

	fmt.Println(Sqrt(c2))
}