SOLUTION: a lighthouse casts a 72- yard shadow at the same time as a 32-foot tall bill board casts a 19-foot shadow what is the height of the lighthouse
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-> SOLUTION: a lighthouse casts a 72- yard shadow at the same time as a 32-foot tall bill board casts a 19-foot shadow what is the height of the lighthouse
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Question 314914: a lighthouse casts a 72- yard shadow at the same time as a 32-foot tall bill board casts a 19-foot shadow what is the height of the lighthouse Found 2 solutions by rfer, solver91311:Answer by rfer(16322) (Show Source):
You can put this solution on YOUR website! 32/19=216/x
32x=4104
x=128.25 ft
128.25/3=42.75 yds
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32/19=72/x
32x=1368
x=42.75 yds
Let represent the height of the lighthouse. We know from the proportionality of similar triangles that:
Cross-multiply and solve.
Notes about the precision of your answer. Since 19 will not divide evenly into 32 times 72, you are going to come out with a decimal fraction representing a number of yards of height. However, the least precise measurements in the given data is to the nearest yard. Therefore, the results of any calculations involving these data is properly expressed to the level of precision of the least precise measurement. Hence, it is correct to express your answer to this question rounded to the nearest whole yard, and it is technically incorrect to express the answer to any greater precision.
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