Describe two characteristics of classical civilizations. then, explain how those characteristics differentiate classical civilizations from early river valley civilizations.

Characteristics are:
1) Complex governments - political organizations were more developed in classical civilizations. For example Greece (in Athens free men made political decisions, democracy for adult males), in Rome there was Republic (ruled by aristocrats).
2) Trade and economic systems were more developed in classical civilizations. 
Trade routes were connected by land and sea, for example Han era in China (trade along the Silk Road)

Remember soh-cah-toasoh: cah: toa: now, looking at the picture we can see that we have an angle, the hypotenuse and want to find the value of the adjacent side to the angle. so we use cah to find the adjacent angle. plug in what we have: we need to solve for x now so we get it by itself on one side: plug this into your calculator and you'll find that: