none of them are a right angle since there isn't an angle on any of those measurements that are 90 degrees.
The Proterozoic division of the geological time scale is an era of the Phanerozoic eon. The Proterozoic division began 2.5 billion years ago and ended 542.0 million years ago.
Jin Dynasty which was in China and for east africa I cant find or remember anything from their the closest is the Islamic empire.