垂心 - DyGeom.m on Mathematica+KETpic

SetDirectory[NotebookDirectory[]];
<< DyGeom.m
p1 = FreePoint[{-4, -1, pointname -> "A", pointposition -> "sw"]
p2 = FreePoint[{1, 4, pointname -> "B", pointposition -> "nw"]
p3 = FreePoint[{2, -1, pointname -> "C", pointposition -> "ne"]
l1 = ConnectPoints[p1, p2, clipping -> {p1, p2}]
l2 = ConnectPoints[p2, p3, clipping -> {p2, p3}]
l3 = ConnectPoints[p3, p1, clipping -> {p3, p1}]
l4 = PerpendicularLine[p3, l1]
l5 = PerpendicularLine[p1, l2]
l6 = PerpendicularLine[p2, l3]
p4 = IntersectionLL[l4, l5, pointname -> "H", pointposition -> "sw4"]
q1 = IntersectionLL[l1, l4]
q2 = IntersectionLL[l2, l5]
q3 = IntersectionLL[l3, l6]
l4 = AddOption[l4, clipping -> {p3, q1}]
l5 = AddOption[l5, clipping -> {p1, q2}]
l6 = AddOption[l6, clipping -> {p2, q3}]
DrawConstruction[p1, p2, p3, p4, l1, l2, l3, l4, l5, l6]

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