# analytical geometry

posted by
**manjula**
.

two edges PQ,RS of a tetrahedron PQRS are perpendicular,show that the distance between the mid-points of PS and QR is equal to the distance between the mid points of PR and QS

posted by
**manjula**
.

two edges PQ,RS of a tetrahedron PQRS are perpendicular,show that the distance between the mid-points of PS and QR is equal to the distance between the mid points of PR and QS