You can rotate presentation shapes either in the graphical editor or by specifying the required rotation angle in the shape properties.
Please note that you cannot rotate pixels, GIS maps and view areas.
Presentation shapes can be rotated directly in the graphical editor by dragging the shape's rotation point.
To show the rotation point of the shape
In order to 
Use the mouse like described here 
Description 
Rotate the shape by angles restricted by multiples 
Click on the rotation point with the left mouse button and, while holding the button down, move the mouse in the required rotation direction:

It is the most frequently used type of rotation. Rotating the mouse right near the rotation point, you restrict the rotation angles to multiples of 15 degrees (15, 30, ...).
Shape rotated by 15 degrees Moving the mouse aside from the rotation point while dragging, you restrict angles to multiples of 5 degrees (5, 10, ...), moving a little bit more aside  you restrict angles to integer values (1, 2, ...). 
Rotate the shape by any angle 
Press Alt, then click the rotation point and while holding both Alt and the left mouse button down, move the mouse in the required rotation direction: 
This type of rotation enables to rotate shapes by any angles (not only by integer ones as in the case described above).
Shape rotated by 5,79... degrees 
Rotate the shape by an angle multiple of 90 degrees 
Press Shift, then click the rotation point and while holding both Shift and the left mouse button down, move the mouse in the required rotation direction: 
The shape gets rotated by angles multiple of 90 degrees (90, 180, 270 degrees).
Shape rotated by 90 degrees 
When you rotate a shape, it rotates around its rotation point. For the majority of shapes (rectangle, image, etc.) it is the shape's topleft corner.
You may need to rotate a shape around its center, which requires shifting the shape's rotation point. It can be achieved by including the shape in a group: in this case, the group's origin will be used as a rotation point.
A new group containing the shape will be created. The group's rotation point is located in the center of the shape, so you can rotate the group and thus the rectangle around its center.
To define shape's rotation angle in degrees
To rotate a shape dynamically at the model runtime, specify an expression that will be reevaluated at the model runtime and return the shape's rotation angle. This can be done in the Rotation property located in the Position and size section of the shape properties.
Please note that while in the static Rotation property (located on the Position and size section) you define angles in degrees, the expression specified in the dynamic Rotation field returns not degrees, but radians.