Write a program that prompts the user to enter three points

$($

x

$1$

$,$

$$y

$1$

$)$

$,$

$($

x

$2$

$,$

$$y

$2$

$)$

$,$

$($

x

$3$

$,$

$$y

$3$

$)$

$$of a triangle and displays its area.

The formula for computing the area of a triangle is:

s

$=$

$($

side

$1$

$+$

$$side

$2$

$+$

$$side

$3$

$)$

$/$

$2$

area

$=$

$$square root of s

$($

s

$-$

$$side

$1$

$)$

$($

s

$-$

$$side

$2$

$)$

$($

s

$-$

$$side

$3$

$)$