You can find out where the majority of the Register families were living before they immigrated to the U.S and learn where to focus your search for foreign records. Immigration records can tell you an ancestor's name, ship name, port of departure, port of arrival, and destination.
So the general rule is: Sum of Interior Angles = (n -2) Ã 180 Â°. Each Angle (of a Regular Polygon) = (n -2) Ã 180 Â° / n. Perhaps an example will help:
Every interior and exterior angle forms a supplementary pair, so if you add all the interior angles and all the exterior angles, you'll get 4 straight lines, or 720 degrees. But since the sum of the interior angles is 360 degrees, that means the sum of the exterior angles is 720 - 360 = 360 degrees! But hang on a second, you might think, That's all well and good for a quadrilateral like the one you've drawn there, but not all quadrilaterals look the same.