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.
Not all things with four sides and 90 degree angles are squares or rectangles! Sometimes the angles in these 4-sided shapes are less than (or greater than) 90 degrees, causing them to have a slightly odd shape. These are called quadrilaterals and come in a few different varieties. In this tutorial, you'll learn about them.