SOLUTION: A tree casts a shadow of 30 feet long. At the same time, a vertical rod 21 feet high casts a shadow 9 feet long. How tall is the tree?

Question 744943: A tree casts a shadow of 30 feet long. At the same time, a vertical rod 21 feet high casts a shadow 9 feet long. How tall is the tree?
Answer by Cromlix(4381) (Show Source): You can put this solution on YOUR website!
This a similar triangle problem.
If you consider the two horizontal
sides (shadows) as a ratio 30/9
Consider the corresponding vertical sides
x and 21
30/9 = x/21 Cross multiply
9x = 630
x = 70
Therefore the tree is 70 feet high.
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