ANSWER
The length of NR is
EXPLANATION
The centroids divides the medians in the ratio
For instance
But
We substitute all these values in to the above relation to obtain,
This can be rewritten as
We cross multiply to obtain,
This implies that,
We group like terms to obtain,
This simplifies to give us,
We can now determine each length as follows,
From the diagram,
The length of NR is
EXPLANATION
The centroids divides the medians in the ratio
For instance
But
We substitute all these values in to the above relation to obtain,
This can be rewritten as
We cross multiply to obtain,
This implies that,
We group like terms to obtain,
This simplifies to give us,
We can now determine each length as follows,
From the diagram,