The line graph shows the growth of a plant over time.
A line graph titled Height of a Plant has number of weeks on the x-axis and height (inches) on the y-axis. At 1 week the height is 2, at 2 weeks the height is 5, at 3 weeks the height is 8, at 4 weeks the height is 12, at 5 weeks the height is 16, at 6 weeks the height is 19.
How many inches did the height of the plant increase between weeks 3 and 4?