Question: how to calculate percentage increase in a graph?
Answer: The y-axis of a graph is the vertical axis. ... 
The x-axis is the horizontal axis of a graph. ... 
Consider a line graph that shows the growth of a plant over a 10-day period. ... 
15 inches - 10 inches = 5 inches.
(5 in / 10 in) = .5 x 100 = 50.