How to rotate whole table in Pages document?
Rotate an image, shape, text box, line, arrow, or video Select the
  object, then in the Format  sidebar, click the Arrange tab.
  
  Drag the Rotate wheel, or enter a degree value in the adjacent field
  to specify the angle at which you want to rotate the object.
  
  Tip: You can also press the Command key while your pointer is over a
  white square on the object, then drag to rotate.


Source: Pages for Mac: Resize, rotate, and flip objects in a Pages document