If $A(1, 1, 2), B(2, 1, 2), C(2, 2, 1)$,then $A, B, C$ are $........$

The centroid of a triangle $ABC$ is at the point $(1,1,1)$. If the coordinates of $A$ and $B$ are $(3,-5,7)$ and $(-1,7,-6)$ respectively,find the coordinates of the point $C$.

The circumradius of the triangle formed by the points $A(2, -1, 1)$,$B(1, -3, -5)$,and $C(3, -4, -4)$ is:

If $a>0, b>0$, then the maximum area of the parallelogram whose three vertices are $O(0,0)$, $A(a \cos \theta, b \sin \theta)$, and $B(a \cos \theta, -b \sin \theta)$ is

Verify that the points $A(-1, 2, 1)$,$B(1, -2, 5)$,$C(4, -7, 8)$,and $D(2, -3, 4)$ are the vertices of a parallelogram.

The incenter of the triangle formed by the points $(0,0,0), (3,0,0)$ and $(0,4,0)$ is