SOLUTION: Austin is landscaping a yard. To see how well a tree shades an area of the yard, he needs to know the tree’s height.The tree’s shadow is 18 ft long at the same time Austin’s shadow

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Question 945782: Austin is landscaping a yard. To see how well a tree shades an area of the yard, he needs to know the tree’s height.The tree’s shadow is 18 ft long at the same time Austin’s shadow is 4 ft long. If Austin is 6 ft tall, how tall is the tree?
We are talking about similar triangles in the topic, so are the triangles supposedly similar? And yes, how tall is the tree and how do I get it? Thank you in advance.
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
The tree:
y tall, shadow 18 feet toward the right.

Austin:
6 feet tall, shadow 4 feet toward the right.

Draw those to make understanding the picture easier.

The triangles are similar and corresponding sides are in proportion.
highlight_green%28y%2F6=18%2F4%29

%28y%2F6%296=%2818%2F4%296
y=18%2A2%2A3%2F%282%2A2%29
'
y=%282%2A9%2A2%2A3%29%2F%282%2A2%29
'
y=9%2A3

highlight%28y=27%29