Rotate
The Rotate tool rotates selected elements by an angle about the centroid of each element or the bounds of the selection of elements.
Select the elements you want to rotate and then click the Rotate button.
A dialog will open at the top of the window showing presets for common angles, as well as a box where you can enter a specific angle of rotation. Mouse over any of the preset angles to see a preview. Click the angle to accept. For other angles, fill in the rotation angle and the preview will update dynamically.
Click the Rotate button to accept. Pressing Enter after changing the angle will accept the current angle as well.