Answer:
N is the midpoint of MO
Step-by-step explanation:
Given
See attachment for triangles
Required
Additional information to prove
From the attachment, we already have:
and 
The additional information that must be true for
to be true is: <em>N is the midpoint of MO</em>
Because this piece of information proves that:

<em>Which in other words makes </em>
<em> </em>