Congruent is a complicated word with an easy meaning - it just means 'the same as'. If two shapes are congruent, it just means that they have the same shape andthe same size.
For two shapes to be congruent, then one shape will fit exactly into the other shape by rotating, reflecting or translating. They have the same angles, same lengths of side and the same area.
Similar means 'alike'. If two shapes are similar, then
they are alike, but not exactly the same.
They have the same shape butnot the same size.
For two shapes to be similar, the shapes will not fit exactly into the other shape by rotating, reflecting or translating. They have the same angles, but different lengths of side and different areas.
Compare these shapes to see if they are congruent or similar.