△HDR can be mapped onto \triangle SNZ△SNZ by a rotation. If \text{m}\angle D = 128^{\circ}m∠D=128 ∘
, find \text{m}\angle Sm∠S.
Since \triangle HDR△HDR can be mapped onto \triangle SNZ△SNZ by a rigid motion, \triangle HDR \cong \triangle SNZ△HDR≅△SNZ.