You plant a tree that is 36 inches tall. after one year, the tree is 43 inches tall. which expression describes the percent of increase in the tree's height?

The tree increased its height by 19.44%

(43 - 36) ÷ 36 = 7 ÷ 36 = 0.1944 * 100% = 19.44%

36 is the basis of the equation. It is the 100%
7 is the increase in height (inches). It is the 19.44%
43 is the total height. It is 119.44% height of the tree.

Whatever height the tree grow to, if the question is percentage since it was planted, then 36 inches is the basis.

If the problem refers to the height increase based on the latest height measurement, then 43 inches is the basis.

If the 7 inches increase in height is constant every year. Then, an equation will show:

y = 36 + 7x
where y is the total growth through the years. 36 is the initial height, 7 is the constant rate of growth, and x is the number of years the tree has grown.