A. Use a Proportion
Strategy 1: Use a Proportion
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Example 1 |
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Convert 20 kilometres to miles.
A conversion ratio between kilometres and miles is 1 km = 0.621 mi , which can be written as «math style=¨font-family:`Times New Roman`¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mfrac mathcolor=¨#B94A48¨»«mrow»«mn»1«/mn»«mspace width=¨0.33em¨/»«mi»km«/mi»«/mrow»«mrow»«mn»0«/mn»«mi mathvariant=¨normal¨».«/mi»«mn»621«/mn»«mspace width=¨0.33em¨/»«mi»mi«/mi»«/mrow»«/mfrac»«mo mathcolor=¨#B94A48¨»=«/mo»«mn mathcolor=¨#B94A48¨»1«/mn»«mspace mathcolor=¨#B94A48¨ width=¨0.33em¨/»«mi mathcolor=¨#B94A48¨»or«/mi»«mspace mathcolor=¨#B94A48¨ width=¨0.33em¨/»«mfrac mathcolor=¨#B94A48¨»«mrow»«mn»0«/mn»«mi mathvariant=¨normal¨».«/mi»«mn»621«/mn»«mspace width=¨0.33em¨/»«mi»mi«/mi»«/mrow»«mrow»«mn»1«/mn»«mspace width=¨0.33em¨/»«mi»km«/mi»«/mrow»«/mfrac»«mo mathcolor=¨#B94A48¨»=«/mo»«mn mathcolor=¨#B94A48¨»1«/mn»«/math» A proportion can be set up as follows. «math style=¨font-family:`Times New Roman`¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mtable mathcolor=¨#B94A48¨»«mtr»«mtd»«mfrac»«mi»x«/mi»«mrow»«mn»20«/mn»«mspace width=¨0.33em¨/»«mi»km«/mi»«/mrow»«/mfrac»«mo»=«/mo»«mfrac»«mrow»«mn»0«/mn»«mi mathvariant=¨normal¨».«/mi»«mn»621«/mn»«mspace width=¨0.33em¨/»«mi»mi«/mi»«/mrow»«mrow»«mn»1«/mn»«mspace width=¨0.33em¨/»«mi»km«/mi»«/mrow»«/mfrac»«/mtd»«/mtr»«mtr»«mtd»«mfrac»«mi»x«/mi»«menclose notation=¨updiagonalstrike¨»«mn»20«/mn»«mspace width=¨0.33em¨/»«mi»km«/mi»«/menclose»«/mfrac»«mo»§#183;«/mo»«menclose notation=¨updiagonalstrike¨»«mn»20«/mn»«mspace width=¨0.33em¨/»«mi»km«/mi»«/menclose»«mo»=«/mo»«mfrac»«mrow»«mn»0«/mn»«mi mathvariant=¨normal¨».«/mi»«mn»621«/mn»«mspace width=¨0.33em¨/»«mi»mi«/mi»«/mrow»«mrow»«mn»1«/mn»«mspace width=¨0.33em¨/»«menclose notation=¨updiagonalstrike¨»«mi»km«/mi»«/menclose»«/mrow»«/mfrac»«mo»§#183;«/mo»«mn»20«/mn»«mspace width=¨0.33em¨/»«menclose notation=¨updiagonalstrike¨»«mi»km«/mi»«/menclose»«/mtd»«/mtr»«mtr»«mtd»«mi»x«/mi»«mo»=«/mo»«mn»12«/mn»«mi mathvariant=¨normal¨».«/mi»«mn»42«/mn»«mspace width=¨0.33em¨/»«mi»mi«/mi»«/mtd»«/mtr»«/mtable»«/math» |
Strategy 2: Unit Analysis
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Example 2 |
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How many kilograms is this?
«math style=¨font-family:`Times New Roman`¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mn mathcolor=¨#B94A48¨»137«/mn»«mspace mathcolor=¨#B94A48¨ width=¨0.33em¨/»«mi mathcolor=¨#B94A48¨»lbs«/mi»«mo mathcolor=¨#B94A48¨»§#183;«/mo»«mfrac mathcolor=¨#B94A48¨»«mrow»«mn»0«/mn»«mi mathvariant=¨normal¨».«/mi»«mn»454«/mn»«mspace width=¨0.33em¨/»«mi»kg«/mi»«/mrow»«mrow»«mn»1«/mn»«mspace width=¨0.33em¨/»«mi»lbs«/mi»«/mrow»«/mfrac»«mo mathcolor=¨#B94A48¨»=«/mo»«mn mathcolor=¨#B94A48¨»62«/mn»«mi mathvariant=¨normal¨ mathcolor=¨#B94A48¨».«/mi»«mn mathcolor=¨#B94A48¨»198«/mn»«mspace mathcolor=¨#B94A48¨ width=¨0.33em¨/»«mi mathcolor=¨#B94A48¨»kg«/mi»«/math» |
The worldwide average weight of an adult is approximately 137 lbs.