Determine whether the triangles are similar. if so, what is the similarity statement and the postulate or theorem used?

This is the concept of geometry, we are required to determine if the triangles are similar;
The following ways can be used to determine the similarity of triangles;
SSS- side-side-postulate
ASA- angle side angle side
AAS- angle angle side
SAS- Side angle side

Gen the following corresponding sides are similar by SSS;
OJ≡OM
OK≡ON
JK≡MN

Therefore we conclude that ΔOMN is similar to ΔOJK by SSS

The linear equation is: y=ax+b