Question

Henry and his family are eating at a rotating restaurant at the top of a tower. The restaurant rotates clockwise 90°
every 15 minutes. When the family sat down, their table was located at (-4, 4)
in relation to the center of the restaurant. Where is their table located 30 minutes later, in relation to the center of the restaurant? Use complete sentences to justify your answer.


WRITER

Answer 1

The restaurant turns 90° clockwise every 15 minutes, so in 30 minutes it turns 180° clockwise (two 90° turns). A 180° rotation about the origin sends (x,y) to (−x,−y). Thus (-4, 4) becomes (4, -4). Therefore the table is at (4, -4) relative to the center 30 minutes later.