Question 103086
You can solve this problem using proportions that are set up as follows:
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{{{(Height)/(Shadow) = (Height)/(Shadow)}}}
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The height of the woman is 5 ft 6 inches and this is 5.5 feet. Her shadow is 12 ft long. 
Substituting these values results in:
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{{{(5.5)/(12) = (Height)/(Shadow)}}}
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The shadow of the tree is 45 feet. Substitute this and you get:
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{{{(5.5)/(12) = (Height)/45}}}
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You can get rid of the denominator of 45 by multiplying both sides of the equation by 45.
When you do that the equation becomes:
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{{{((45)*(5.5))/(12) = ((cross(45))*(Height))/(cross(45))}}}
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You are now left with the equation:
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{{{((45)*(5.5))/12 = (Height)}}}
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Solve for the Height of the tree by multiplying out the numerator of 45*5.5 and dividing that
product by 12 to get:
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{{{(Height) = ((45)*(5.5))/12 = 247.5/12= 20.625}}}
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The tree is 20.625 feet tall. This converts to 20 ft 7.5 inches.
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Hope this helps you to understand the problem a little better ...
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