△HDR can be mapped onto \triangle SNZ△SNZ by a rotation. If \text{m}\angle D = 128^{\circ}m∠D=128
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, 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.
