The tomb of Ramses IX was built in approximately 1,140 BC. There is evidence of a right which has the legs of the right triangles and hypotenuse as 3,4 and 5 respectively. Egyptians acquired the concept of how to construct a right triangle from a rope with 12 knots separated equally. When three people drew the rope taut as shown below, it obtained a right angle. This from a triangle called the right triangle as shown: