it tells you data
bar graph
if you are graphing a change over time, a line graph. if you are comparing data, it's a bar graph.
A Mercator projection map would be useful for comparing the sizes of continents as it preserves the shapes of continents but distorts their sizes, making it easier to visually compare.
A bar graph is useful for showing the amount of the items yours comparing. This is great for a survey too.
A comparing graph is a graph that compares number to see if they similar or different.
If they things you are comparing part of a whole, pie graph. If not, bar graph.
A double bar graph
A pie graph is another name for a circle graph: the numbers are represented by wedges which look something like thicker and thinner slices of pie. It is used (and useful) when comparing the proportions of numbers which together add up to 100% of something.
bar graph because you can see them more clearly it also depends on what u r comparing
A scatter graph.
Any type of graph, really.
you would use a line graph