The third number multiplied by the first number

The sum of all three numbers divided by the third numberOptional Bonus Task $1$

Let's try some slightly more complex maths. Follow these steps:

Create a new Python file in the Dropbox folder for this task, and call it

optional$\_$task$1.$py$.$

Ask the user to enter the lengths of all three sides of a triangle.

Calculate the area of the triangle.

Print out the area.

Hints

If sidel, side $2$ and side $3$ are the sides of the triangle:

sidel $+$ side $2+$side$3$ and

$,$ area $=\sqrt[\phantom{2}]{?}(s(s-a{)}^{**}(s-b{)}^{**}(s-c))$

You'll need to be able to calculate the square root $($this may help$)$

Optional Bonus Task $2$