okay - math is not my thing! I need help on a conversion problem...

[hmsch4me]

Question: 1,400 km = ? miles (1.609km = 1mile)

 

So, 1km is longer than 1 mile, so I multiply 1.609 x 1400?

 

Answer books says that you divide 1400 by 1.609, stating that a mile is longer than a km!

 

I'm going crazy here - please help!

[Matryoshka]

No, a mile is longer than a km (book is right).

 

1.609 km = 1 mile.

 

That means that if you were walking, you would have traveled 1.609 km (more than one) when you hit the one mile mark.

 

If it helps, think

 

4 quarts = 1 gallon or

12 inches = 1 foot.

 

The unit with the higher number in the equivalency is the smaller unit.

[sandra in va]

Question: 1,400 km = ? miles (1.609km = 1mile)

 

So, 1km is longer than 1 mile, so I multiply 1.609 x 1400?

 

Answer books says that you divide 1400 by 1.609, stating that a mile is longer than a km!

 

I'm going crazy here - please help!

 

 

I always think in ratios - keeping like units together

 

1400 km = x miles

1.609 km... 1 mile

 

or

 

1400 km = 1.609 km

x miles ......1 mile

 

(ignore the dots - I couldn't get the fractions spaced appropriately with the space bar!)

 

Then solve for the unknown (cross-multiply and divide). This way you don't have to worry about the conversion (i.e. which one is bigger) - let the units guide your problem. Setting it up like this helps doing problems in the sciences, too. (Btw, a km is less than a mile since there are 1.609 of them in one mile. Tricky!) :001_smile:

 

Hth,

Edited November 13, 2008 by sandra in va

[RootAnn]

I do it very similiar to sandra in va.

 

1,400 km = ? miles (1.609km = 1mile)

Make the units work for you.

You have km and you want to end up with miles.

 

1,400 km * (1 mile / 1.609 km) --> this cancels out the km and leaves you with just miles "on the top". This is how we learned units in science class and makes sense. Although, it is hard type out and have make sense. Sandra in VA did a great job showing you with ratios. I just find that the cross-multiply & divide thing scares some non-math types. The way I show above just has you multiplying by the ratio with the units matching to cancel out.

[sandra in va]

The way I show above just has you multiplying by the ratio with the units matching to cancel out.

 

:iagree:Yes! This is especially better when you have a string of conversions to do. The ratios I wrote are okay for visualizing one conversion, but would get unnecessarily tedious if doing more than one conversion (like in many science problems). Great point.

Edited November 14, 2008 by sandra in va

[Ellie]

is (1) the importance of doing the conversions, because if you lived somewhere that used metrics you would just...use metrics; you would't be converting from anything to anything, and (2) why put that much thought into using a different measuring system, when ya gotta know that the U.S. is *NOT* going to go to all metrics anyway. :D

[sandra in va]

is (1) the importance of doing the conversions, because if you lived somewhere that used metrics you would just...use metrics; you would't be converting from anything to anything, and (2) why put that much thought into using a different measuring system, when ya gotta know that the U.S. is *NOT* going to go to all metrics anyway. :D

 

 

:lol:

 

Too funny.

[AnneC]

is (1) the importance of doing the conversions, because if you lived somewhere that used metrics you would just...use metrics; you would't be converting from anything to anything, and (2) why put that much thought into using a different measuring system, when ya gotta know that the U.S. is *NOT* going to go to all metrics anyway. :D

 

But if you live somewhere that uses metrics (like Australia) but you cook or sew, you have to learn to do conversions otherwise you can't cook all the yummy American recipes.:001_smile: Same with books, if you read a book with measurements in miles you have to convert them to km to figure out the distances!

[Garga]

Or type " convert 6 kilometers to miles" (or vice versa) in your google search. The answer pops up.

[Ellie]

But if you live somewhere that uses metrics (like Australia) but you cook or sew, you have to learn to do conversions otherwise you can't cook all the yummy American recipes.:001_smile: Same with books, if you read a book with measurements in miles you have to convert them to km to figure out the distances!

 

In that case, I'd learn them. It just doesn't make sense to me for that to be a requirement for the rest of us :-)

[Matryoshka]

In that case, I'd learn them. It just doesn't make sense to me for that to be a requirement for the rest of us :-)

 

I am fairly comfortable in both systems, being an American who has lived in Europe.

 

But I'm with you, I don't see the need to drill conversions US/metric. I think it's important to know about what the different units mean, and have a general idea of how much they are, and how to convert them if necessary, but drilling exact conversions? I think that actually may impede real understanding.

 

Like, I think it's important to know that there are a bit more than 1 1/2 km to a mile, to estimate in one's head about how far a distance given in km is. So you can understand, how far away is 100km, and about how long would it take me to drive there?

 

For temperature, you just need to know the same info you do in Farenheit

 

0 C - freezing, wear a coat

10 - chilly, wear a light jacket

20 - nice, enjoy the weather!

30 - hot hot hot!

180 - bake a cake

200 - bake a pizza

 

If I bake in metric, I just buy metric measures. A meter is a bit more than a yard. 30 cm is about a foot. A kilogram is about two pounds.

 

I like that Singapore (that we use) teaches mainly metric, and while ithe US edition does teach "standard" measurements briefly, there is no conversion between systems. A lot of conversion within systems, but not across. This makes sense to me.

 

I figure US measurements are really only necessary for everyday life, in which not a ton of math is involved. Any field that requires a large amount of math with measurement (engineering, sciences, mathematics) is going to be using metric anyway, even in the US. (except maybe construction?)

[kiana]

Of course, you could be NASA and have your Mars lander crash because you forgot to convert :)

 

More seriously -- for the average person in America, no, converting to metric is probably not that much use. But for anyone who will do science, they'll need it then (at least, I saw it in basic chemistry/physics). And even for someone in America, converting between inches/feet or between tablespoons/teaspoons or between cups/pints is useful. So while drilling the precise conversion factors is likely to be of little use, knowing how to convert given a conversion factor is of use.