Is 9 + 10 really 21 ??

Angle onp = 43°angle lno = 137°angle mnp = 137°

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.