The rotationAngle read-only property of the Touch interface returns the rotation angle, in degrees, of the contact area ellipse defined by Touch.radiusX and Touch.radiusY. The value may be between 0 and 90. Together, these three values describe an ellipse that approximates the size and shape of the area of contact between the user and the screen. This may be a relatively large ellipse representing the contact between a fingertip and the screen or a small area representing the tip of a stylus, for example.