Can Points M and N Trisect a Parallelogram's Diagonal and Sides?

[Van Allen]

i need to finish this before i move on tomorrow. any help? thanks

Points M and N are the midpoints of opposite sides of paralellogram ABCD. Prove that:
a) R and S trisect diagonal BD
b) R is a points of trisection of AN and S is a point of trisection of MC.

 

[pseudovector]

Try examining the proportions between the triangles BRN, BSC, DMS,DAR

 

[vaishakh]

Prove AN||CM and AM = CN. Now go with triangle ABN and CMD. Then compare triangles as Pseudo said like BRN and ARD and then BRN and DSM