U$1\_$Final: Write a program that tells the user if three lengths, entered by the user, of a triangle form an

equilateral $($all $3$ sides are equal$),$ isosceles $(2$ sides are equal$),$ scalene $($all sides are different$)$ or cannot

form a triangle. If the lengths make a triangle, calculate the perimeter and area of the triangle. Assume

the user will type positive decimal numbers. Also, ask the user if they want to run the program again to

be able to enter another set of numbers. When asking the user, the program should recognize input of $Y,$

y$,$ N$,$ and n$.$ Any other answer would tell the user that they entered an invalid response $($see sample

output$).$

Here are the formulas needed, where are the sides of the triangle:

$P=a+b+c$

$S=\frac{a+b+c}{2}$

$A=\sqrt[\phantom{2}]{S(S-a)(S-b)(S-c)}$

Note: Technically an equilateral triangle is also an isosceles triangle.

Sample Output $($yours should look and function in a same manner$)$:

welcome to the triangle der$-$terminator'!

Enter three side lengths of a triangle: $123$

$1.,2.,$ and $3.$ cannot form a triangle.

Do you want to enter another set $(\frac{y}{n})?$ y

Fnter three side lengths of a triangle: $>34$

$2\mathrm{.}6,3\mathrm{.}6,$ and $4\mathrm{.}0$ forms a scalene triangle.

Perimeter $=9\mathrm{.}6$

Area $=2\mathrm{.}9047375096555625$

Do you want to enter another set $(\frac{y}{n})?$ maybe

maybe is an invalid input

Do you want to enter another set $(\frac{y}{n})?$ Y

Enter three side lengths of a triangle: $3,34$

$3\mathrm{.}6,3\mathrm{.}6,$ and $4\mathrm{.}6$ forms an isosceles triangle.

Perimeter $=10\mathrm{.}0$

Area $=4\mathrm{.}47213595499958$

Do you want to enter arother set $(\frac{y}{n})?n$

thank you for using this program.