examday

/TMUA

A rectangular sheet $ABCD$ is folded along the diagonal $AC$, so that the two triangular parts lie in different planes. In the folded position,

and the directions of $AB$ and $CD$ are perpendicular.

What is the volume of the tetrahedron with vertices $A,B,C,D$?

The volume of a tetrahedron is one third of the area of a triangular face multiplied by the perpendicular distance of the opposite vertex from that face.