Drawing a line at a specific angle can be difficult for fractional angles (for example, 23.34 degrees). Likewise, rotating an object to a fractional angle can be difficult. You can save time and steps by drawing the line horizontally or vertically, then use the Mouse Constraint feature while rotating the line. Likewise, this technique can be used to rotate any object to an exact fractional angle.
1. Select the Preferences command from the Layout pulldown menu. (Shortcut: double-click on the corner-center control.)
2. Select the Mouse Option.
3. Click the radio button marked "Custom" under Mouse Constraint, and enter the degrees rotation into the Entry box.
4. Click OK to close the Preferences window.
5. Select Rotate, and rotate the object while holding down the shift key.
The rotation will be limited to 90 degree increments and the custom angle. For example, setting a custom mouse constraint of 15 degrees limits rotation to 0, 15, 75, 90, 105, 165, 180, 195, 255, 270, 285 and 345 degrees.