Answer:
The tree is 28 feet tall.
Explanation:
It is given that:
Height of flag pole = 8 feet
Shadow of flag pole = 6 feet
Ratio of height to shadow = 8 : 6
Shadow of nearby tree = 21 feet
Height of nearby tree = x
Ratio of height to shadow = x : 21
8 : 6 :: x : 21
Product of means = Product of extremes
6x = 8*21
6x = 168
Dividing both sides by 6

Therefore,
The tree is 28 feet tall.