How can the scaling of a line graph be used to mislead a reader?

Misleading may be present even though all graphs may share the same data, and even the slope of the data is the same. If the way the data is plotted is not correct, it can change the visual appearance of the angle made by the line on the graph. This is so because each plot has different scales on its vertical axis. As the scales are not correctly shown then there is where the misleading appears.

You can find it by multiplying the areas it show u

Ireally don’t understand your problem do you have a better picture of it