you could do it like that.
you draw all the vertices and add a scale variable for scaling but also add a negative translation of the first vertex+scaling. so you move your shape back to 0,0 and can than relocate it with another translation (in this case width/2,height/2)

1.  
   void setup() {
     size(600,400);
     smooth();
     background(255);
   
   }
   
   void draw() {
     background(255);
   fill(0,100);
   stroke(255,0,0);
   
   int scale = 1000;
   
   translate(width/2,height/2);
   translate(-775.53375*scale,-737.77734*scale);
   
   
   beginShape();
    vertex( 775.53375*scale,737.77734*scale);
    vertex( 775.52997*scale,737.7678*scale);
    vertex( 775.4771*scale,737.788*scale);
    vertex( 775.5931*scale,737.8874*scale);
    vertex( 775.5956*scale,737.8857*scale);
   
   endShape(CLOSE);
   
   }