var index1=Math.round(Math.random()*(4-1))+1; var question1=new Array(5); var truevalue1=new Array(5); var closevalue1=new Array(5); question1[0]='

10,600 in to m

m

'; truevalue1[0]='269'; closevalue1[0]='269.24'; question1[1]='

10,600 in to m

m

'; truevalue1[1]='269'; closevalue1[1]='269.24'; question1[2]='

17,600 mm to yards

yd

'; truevalue1[2]='19.2'; closevalue1[2]='19.24759405'; question1[3]='

2.66 miles to cm

cm

'; truevalue1[3]='428,000'; closevalue1[3]='428,085.504'; question1[4]='

7.63 x 10⁶

m to ft

ft

'; truevalue1[4]='25.0'; closevalue1[4]='25.03280839'; question1[5]='

16.8 yd to m

m

'; truevalue1[5]='15.4'; closevalue1[5]='15.36192'; window.document.write('

Metric-English Conversions

A. Metric-English Relationships:
Since the United States still uses the English system for measurements, it may be necessary on occasion to convert a measurement from the English to the Metric System, or vice versa. In order to do this we need some relationships of mass, length, and volume for these two systems.

Many possible relationships for mass could be used. For example, 1 kg = 2.2 lb, 1 ounce = 28.4 g, 1 ton = 908 kg, etc. Let´s set up a convenient relationship for mass, length, and volume, that uses units that are normally encountered in the lab or ordinary everyday life.

	English	Metric
Mass	1 pound (lb)	454 g
Length	1 inch (in)=	2.54 cm
Volume	1 quart (qt)	946 mL

Notice that the length relationship is exact, while the mass and volume relationships are approximations. When you perform conversions involving mass or volume, remember that the conversion factor relating the two systems has to be considered when you round off the answer.

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B. Length:
Let´s try a conversion of an English length to the corresponding Metric value. Convert 7.60 feet to meters.

The sequence of conversions would be:

	12 in		2.54 cm		1 m
7.60 ft x		x		x
	1 ft		1 in		10² cm

The units now cancel out to give only the desired unit of meters.

	12 in		2.54 cm		1 m
7.60 ft x		x		x
	1 ft		1 in		10² cm

Multiply the numbers, and then convert the answer to the appropriate number of significant figures. Since there are three significant figures in the starting value, and all three of the conversion factors are identities, i.e., they are not involved in rounding off, the final answer must have three significant figures.

2.31648 m 2.31 m

Try the following conversion among different length units.

' + question1[index1]); var index2=Math.round(Math.random()*(4-1))+1; var question2=new Array(5); var truevalue2=new Array(5); var closevalue2=new Array(5); var exp2='8'; question2[0]='

1.22 qt to mL

mL

'; truevalue2[0]='1,150'; closevalue2[0]='1,154.12'; question2[1]='

1.22 qt to mL

mL

'; truevalue2[1]='1,150'; closevalue2[1]='1,154.12'; question2[2]='

15,890 mL to gal

gal

'; truevalue2[2]='4.20'; closevalue2[2]='4.19926004'; question2[3]='

8.77 x 10¹⁰

L to qt

qt

'; truevalue2[3]='92,700'; closevalue2[3]='92,706.13107'; question2[4]='

62.9 gal to

L

x 10

L

'; truevalue2[4]='2.38'; closevalue2[4]='2.38013600'; question2[5]='

8,470 cm³ to qt

L

'; truevalue2[5]='8.95'; closevalue2[5]='8.953488372'; window.document.write('

C. Volume:
Now let´s try to convert an English volume to the corresponding Metric volume. Convert 15.0 gal to L.

The sequence of conversions would be:

	4 qt		946 ml		1L
15.0 gal x		x		x
	1 gal		1 qt		103 mL

The units now cancel out to give only the desired unit of liters.

	4 qt		946 ml		1L
15.0 ~~gal~~ x		x		x
	1 ~~gal~~		1 qt		103 ml

Multiply the numbers, and then convert the answer to the appropriate number of significant figures. Since there are three significant figures in the starting value and in the English-Metric conversion factor, (the other two conversion factors are identities, i.e., they are not involved in rounding off), the final answer must have three significant figures.

56.76 L 56.8 L

Try the following conversion among different volume units.

' + question2[index2]); var index3=Math.round(Math.random()*(4-1))+1; var question3=new Array(5); var truevalue3=new Array(5); var closevalue3=new Array(5); question3[0]='

3.76 lb to kg

kg

'; truevalue3[0]='1.71'; closevalue3[0]='1.70704'; question3[1]='

3.76 lb to kg

kg

'; truevalue3[1]='1.71'; closevalue3[1]='1.70704'; question3[2]='

15.3 kg to ounces

oz

'; truevalue3[2]='539'; closevalue3[2]='539.2070483'; question3[3]='

1.50 tons to kg

kg

'; truevalue3[3]='1,360'; closevalue3[3]='1,362'; question3[4]='

4.98 x 10⁶ mg to ounces

oz

'; truevalue3[4]='176'; closevalue3[4]='175.5066078'; question3[5]='

89,350 mg to lb

oz

'; truevalue3[5]='0.197'; closevalue3[5]='0.196806167'; window.document.write('

D. Mass:
Finally, let´s try to convert an English mass to the corresponding Metric mass. Convert 1.582 lb to mg.

The sequence of conversions would be:
454 g 10³ mg
1.582 lb x
x

1 lb 1 g

The units now cancel out to give only the desired unit of milligrams.

	454 g		10³ mg
1.582 lb x		x
	1 lb		1 g

Multiply the numbers, and then convert the answer to the appropriate number of significant figures. Since there are four significant figures in the starting value, and all three of the conversion factors are identities, i.e., they are not involved in rounding off, the final answer must have three significant figures.

7.18228 x 105 mg 7.18 x 105 mg

Try the following conversion among different mass units.

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