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