Need help identifying graphs

What are the names of the graphs used here, what class do you typically learn about them first, and when do you typically use them to solve problems?

http://ritter.tea.state.tx.us/studen...h/p49no29a.gif

http://ritter.tea.state.tx.us/studen...th/p50no32.gif

first is a scatterplot, used to find correlation in data sets, second is some points plotted on a catesian plane.