A pie chart is called a pie chart because it looks like a piece of pie cut into sections... It ISN'T called a cake chart, because a cake chart would be to controversial. - iow (in other words) - a...
One view: Because they just are. Pi is a Greek letter and most mathematics came from the Greeks. Another view: According to wikipedia, it is spelled the same as "pie" because it is named for its...
You cannot have a chart as part of another chart. There may be other solutions, depending on what you want to do. You can have more than one series on the same chart. You can have more than one chart...