Histogram and Frequency Polygon

Topic:
Histogram
Total area of Histograms is equals to area of Frequency polygons. To verify this change values of α and β. Then you can change heights of rectangles NEFM and MGHL. Then you can observe areas of theses rectangles change. Also change sum of area of all rectangles, i.e. Histogram. According to this the area and shape of Frequency Polygon changes.