I was playing with some puzzles and I wanted to create a program in perl that given a set of data , it can figure out if it is a rectangle or not.

the fun part is that I am given 3 points, how do I prove a 4th point will make a rectangle?

I tested for parallel sides to be congruent and have a single 90 angle to prove it

my question is there a module in perl that can take a set of points to figure out lengths, angles...too messy with all little calculations to get lengths

I , as always, looking for some advice in making my program more readable and extending my perl experience with modules

# C(cx,cy)*  ****** *D(?x,?y)
#         *         *
#         *         *
# A(ax,ay)*  ****** * B(bx,by) 
use strict;
use warnings;
use Data::Dump qw(dump);
use Math::Trig;

my @points = ( 1,5,  #point A
               5,5,  #point B
               1,9,  #point C
);

my @new =( 5,9);     #point D will be given by user later (testing my 
+theory)


#lets' get the length of each segment; if parallel sides are equal 
#plus 
#test for 90 angles and IT's a rectangle or square

# GET LENGTHS :
#from A to B 

my $ABx= $points[2]-$points[0];
my $ABy= $points[3]-$points[1];

#points from A to C 

my $ACx= $points[4]-$points[0];
my $ACy= $points[5]-$points[1];

#get length to new points from C TO D
my $CDx= $new[0]-$points[4];
my $CDy= $new[1]-$points[5];
#from B to D
my $BDx= $new[0]-$points[2];
my $BDy= $new[1]-$points[3];

#test if lengths are the same 
#if so, then test if all angles are 90
if ($ABx == $CDx && $ACy == $BDy){
    #find angle
    my $a= atan($ABx/$ACy)*(360/pi);
    $a==90 ? print "this is a Rectangle/square\n" : print "this is a r
+hombus of some sort\n";
}else { print " This shape doesn't have congruent sides; NOT a RECTANG
+LE or Square";}
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