Select the chart, click Inspector in the toolbar, click the Chart inspector button, and then use the Rotation Angle wheel or field.

Click Inspector in the toolbar, click the Metrics inspector button, and then drag the Rotate wheel or use the Angle controls to set the angle of the chart.

Select the chart, hold down the Command key and move the pointer toward an active selection handle until it changes to a curved, double-headed arrow, and then drag a selection handle.

To rotate the chart in 45-degree increments, press the Shift and Command keys while dragging a selection handle or the Rotate wheel.