Which coordinate for points a' and b' would prove that lines ab and a'b' are perpendicular?

Here is the correct answer I just did it 

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.