A compound-complex sentence combines the compound and the complex sentence. The compound part means that it has two or more complete sentences. The complex part means that it has at least one incomplete sentence.
Archimedes' principle. Archimedes' principle states that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces and acts in the upward direction at the center of mass of the displaced fluid. Archimedes' principle is a law of physics fundamental to fluid mechanics. It was formulated by Archimedes of Syracuse.
Archimedes of Syracuse (pronounced ar-ka-meed-eez) is considered one of the greatest mathematicians in history. In fact, he is believed to be one of the three greatest mathematicians along with Isaac Newton and Carl Gauss. His greatest contributions to mathematics were in the area of Geometry. Archimedes was also an accomplished engineer and an inventor. He was believed to have been obsessed with Geometry though.