Answer:
SAS rule
Explanation:
SAS rule ("side, angle side"):
If two sides and the included angle of one triangle are equal to the corresponding sides and angle of another triangle, the triangles are congruent.
The dashes on the lines show they are equal in length., so ON = NQ
The two triangles share one line, NP.
The curved lines on angles ONP and PNQ show that the angles are equal.
So both triangles have 2 sides with an angle inbetween (SAS) and are congruent.