You don't multiply -730 by 3.
You must always add/subtract a multiple of 360 degrees from the angle given. In this case multiply 360 by 3. Add that to your given angle to get +350 degrees for an angle between 0 and 360 degrees. Or multiply 360 by 2 and add that to your given angle to get -10 degrees for an angle between -180 and +180.
Which you want depends on how the principle angle is defined.