Written records of the history of China date from as early as 1500 BC, from the Shang dynasty (c. 1600â1046 BC). Ancient historical texts such as the Records of the Grand Historian (c. 100 BC) and the Bamboo Annals (296 BC) describe a Xia dynasty (c. 2070â1600 BC) before the Shang, but no writing on a durable medium have survived.
A square is a quadrilateral so it has 360 degrees. A square is a quadrilateral so it has 360 degrees.
Facts about right angles. Four right angles fit around a point. The way we define degrees, a full turn around a point is 360Â°, so the measure of each right angle is one fourth of that: 90Â°. In informal speech (not mathematics), right-angle corners are sometimes called square corners even though, as in the shapes above, there is nothing square about the shape.