ffb261…: “Over a great disk”

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Let $(0,0,0)$ , $(2,1,1)$ , $(-1,2,-8)$ and $(1,-1,5)$ be the vertices of a polygon. What is the area $A$ of this polygon? $A=\answer {8\sqrt {\frac {7}{2}}}$ As a gesture of friendship, check out this polygon in $3$ D-space: