Can pls help me with my homework plss

Me complete this proof! prove that a quadrilateral is a square. me with the steps for this proof.

Angle xyz is formed by segments xy and yz on the coordinate grid below: a coordinate plane is shown. angle xyz has endpoints at 3 comma negative 1 and 6 negative 2 and 3 comma negative 3 and measures 36.87 degrees. angle xyz is rotated 270 degrees counterclockwise about the origin to form angle x′y′z′. which statement shows the measure of angle x′y′z′?

Determine which postulate or theorem can be used to prove that lmn =nmo