For what yalues of x is the area of the rectangle shown greater than
100 square units?

Any value of x that is 7 and above will have a total area of greater than 100

The major difference is that a histogram is only used to plot the frequency of score occurrences in a continuous data set that has been divided into classes, called bins.  bar charts, on the other hand, can be used for a great deal of other types ofvariables  including  ordinal  andnominal  data sets.