Question 155516
A man is walking away from a lamppost with a light source 8 meters above the ground. The man is 1.7 meters tall. How long is the man's shadow when he is 15 meters from the lamppost? 
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Draw the picture.
The lamppost is the height of the larger triangle;
The man is height of the smaller SIMILAR triangle.
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Let the base of the larger triangle be x.
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EQUATION:
8 meters/ 1.7 meters = x/x-15

8(x-15) = 1.7x
8x - 120 = 1.7x
6.3x = 120
x = 19.048
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Man's shadow = 19.048-15 = 4.048 meters
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Cheers,
Stan H.