Final answer:
Different scales on graph axes represent two different variables and help with effective data display. It's crucial to select appropriate scales for clarity and accuracy. Line, pie, and bar graphs serve various purposes in data representation.
Step-by-step explanation:
When a graph uses different scales on the two axes, it typically represents two different variables. This practice is not necessarily inaccurate or misleading; rather, it allows for a more effective display of data where each variable may have different units of measurement or ranges of values. It is important to choose a scale that shows all of the data and makes it easy to identify trends. If the scale is too large or too fine, it could make data interpretation more difficult. Moreover, the number of significant figures on the axis values should reflect the precision of the measurements. Graphs can be manipulated to alter perceptions, so they should be regarded with a critical eye to ensure an accurate understanding of the represented data.
As for different types of graphs, line graphs are appropriate for showing trends over time, pie graphs are useful for displaying proportions within a whole, and bar graphs are commonly used for comparing different groups or categories.