Population is increasing in that country in a geometric progression.

那国家的人口正以几何级数。

The E optotype on the chart had 3 limbs of equal length.A regular geometric progression of optotype sizes and distribution was employed to arrange 14 lines with 4 optotypes on each line.

采用三划等的E形视标，视标大小及排列采用均匀的几何，行视标数为4，共14行，两行视标变化进为拶而。