What type of chart would best represent the historical populations of the United States by decade?

A line graph is the most appropriate choice for representing the historical populations of the United States by decade because it effectively shows trends over time. In this context, each point on the graph can represent the population at a specific decade, and connecting these points with a line allows viewers to easily observe patterns, such as growth or decline in population over those decades.

Line graphs are particularly useful for displaying continuous data and identifying trends, making them ideal for demographic changes that occur gradually over time, like population statistics. By presenting the data in this format, one can readily compare the population figures across different decades and see how the population has changed over a significant span of years.

While a pie chart is useful for showing proportions at a single point in time, it doesn’t communicate trends effectively over multiple time periods. A Venn diagram illustrates relationships between groups rather than temporal changes. A histogram displays frequency distributions and is more suited for showing the distribution of data within a single variable rather than depicting changes over time. Hence, the line graph stands out as the best option for showing historical population trends by decade.