Answer
8 feet tall
Work Step by Step
The tree was 4 feet tall when planted and grew 2 feet in 4 years.
Growing 2 feet in 4 years is the same as growing six inches in a year (half a foot).
If the tree was 5 feet tall when planted, and the growth rate didn't change over 6 years, then the tree would be 8 feet tall.
$5+.5*6 = 5+3 = 8$
