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.
A right triangle is a three sided figure with one angle equal to 90 degrees. A 90 degree angle is called a right angle which gives the right triangle its name. We pick one of the two remaining angles and label it c and the third angle we label d. The sum of the angles of any triangle is equal to 180 degrees.