（scheme）(d) (on-parallels? x1 y1 x2 y2 x3 y3 x4 y4), a business of eight parameters (the x and y values of lewd points), avail gentleman if the thread through points (x1,y1) and (x2,y2) is congruous to the thread through points (x3,y3) and (x4,y4). You may exhibit that points (x1, y1) and (x2, y2) are perspicuous, as are (x3, y3) and (x4, y4). (Note: this business can reason any of the businesss defined overhead, barring should confer a amend vindication equable in the cases where points-slope or points-intercept would fall-short.
The not attributable attributableion is to ascertain slop of threads. If couple threads are congruous then there slop must be similar differently they are not attributable attributable attributable congruous.
Bool congruous (x1,y1,x2,y2,x3,y3,x4,y4)
// Slop of principal thread
double m1 =(y2-y1)/(x2-x1);
//Slope of thread couple
double m2= (y4-y3)/(x4-x3);