The missing steps are each right angles and
.
Solution:
Step 1: Given data:



Step 2: In the two polygons,
and

(Each right angle)
Step 3: Given

Step 4: By third angle theorem,
If two angles in one triangle are congruent to the two angles in the other triangle, then the third angles in the triangles also congruent.

Step 5: By the definition of congruent polygons,
If two same shape polygons have all the angles are congruent and all the corresponding sides are congruent then the polygons are congruent.
Hence
.
Therefore the missing steps are each right angles and
.