POLYGON - AREA, CENTER OF GRAVITY. Desription : Compute area and coordinations of center of gravity of polygon, defined by coordinations of vertexs. Inputs : Vertexs in statistic list {x} (x-coordination) and {y} (y-coordination). Outputs : Area, center of gravity. \START81\ \NAME=POLYGON\ \FILE=TI81_3.PRG\ 0\->\S 2\->\I Lbl 1 ({y}(I)+{y}(I-1))({x}(I)-{x}(I-1))+S\->\S IS>(I,Dim{x}) Goto 1 ({y}(1)+{y}(Dim{x}))({x}(1)-{x}(Dim{x}))+S\->\S abs S/2\->\S LinReg 1\->\Arow 2\->\Acol \x-bar\\->\[A](1,1) \y-bar\\->\[A](1,2) xyLine Line({x}(Dim{x}),{y}(Dim{x}),{x}(1),{y}(1)) Disp "AREA" Disp S Disp "CENTER OF GRAVITY" Disp [A] \STOP\