It is adding one little percentage of increase here. or, 1.1 each time....hope that this helps.
Try by dividing this shape into three different squares then find the area of each shape then add them together.
X^3 + h^3 - 3x-3h - x^3 +3x h^3 - 3h h^2 - 2h
------------------------------------- = ------------------ =
h h
336 votes total.
if he got 84 votes 3/7 so you take 84 times 4 (i got four by subracting 3 from 7 and got the remaining votes) and you will get 336 votes. hope this helps! :)