The initial height of the corn plants is 14 1/2 in. and the final height is 20 3/10 in. The difference between these two heights is:
20 3/10 in. - 14 1/2 in. = 5 8/10 in. = 58/10 in.
To find the percent increase, we need to divide the difference by the initial height, and then multiply by 100 to express the answer as a percentage:
percent increase = (difference / initial height) x 100%
percent increase = (58/10 in. / (29/2) in.) x 100%
percent increase = 2 x 100% = 200%
Therefore, the percent increase in the average height of the corn plants during this period is 200%, to the nearest whole percent.