Given:
Figure JKLM is a parallelogram with diagonals MK and JL
the table shows a students proof to show HJM and HLK
We will check the steps to find the incorrect step
so, for step 4
[tex]m\angle\text{JHM}\cong m\angle LHK[/tex]
the angles are congruent because they are vertical angles
So, the answer will be: Step 4
