# How do I convert units if I don't know how many such and such is in such and such?

This is a really basic question.. I have a math problem where I first need to convert miles to meters to actually do the math problem. These kind of math problems always defeat me because I never know how many units of something are in something else. So my math problem showed how to do it and so they said there are 1609 meters/mile. But I didn't know that. Do I have to just remember these conversions in order to do these kind of problems? Am I supposed to automatically know there are 1609 meters per mile? Or is there an actual way to find that out math wise?

### 16 Answers

- PhilomelLv 75 months ago
Google meters to feet or feet to meters or unit one to unit two.

Convert everything to the unit you want to end up with then do the math.

- GBLv 55 months ago
I am so glad we weren't given this sort of maths at school ! Instead we were encouraged to 'think metric'.

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- The_Doc_ManLv 75 months ago
Most dictionaries and many math books contain tables of conversion units. Also several books on physical sciences. Also online converters. The trick isn't to remember all of the frimpin' little numbers. It is to remember where you can find them when you need them.

- llafferLv 75 months ago
Ultimately the conversion you need to remember to go from metric to imperial is:

2.54 cm per inch

If you can drill down any distance to cm or inches, you can then convert from metric to imperial (or the other way around) then work back up to what you want.

So if you want the number of meters in a mile, I would do:

1 mile (5280 ft/mile) (12 in/ft) (2.54 cm/in) (1/100 m/cm) = 1609.644 m

Or if you have access, google the conversion:

- D gLv 75 months ago
you multiply by a conversion factor ..

say you have 10 inches AND want to know how many feet

we know 12 inches/ foot

we also know if we DIVIDE 1/(x/y) we get y/x

so first we need feet / inch

so we take our inch /foot and 1/(12/1) = 1/12

so we have a factor of 1 foot / 12 inches

since our original value we wanted to convert was 10 inches

it is simple to just multiply

10 inches x (1/12) = 10/12 = 5/6 feet

it is that simple

- Steve ALv 75 months ago
You need to know something to do a conversion. Maybe you know 2.54 centimeters = 1 inch. You can work with that

Want meters/mile.

Have cm/inch.

2.54cm/inch * 12inch/foot = 30.48cm/ft

30.48cm/ft * 3feet/yard = 91.44cm/yd

91.44cm/yd * 1meter/100cm = 0.9144m/yd

0.9144m/yd * 1760yd/mile = 1609.344meter/mile

Of course, it is easier if you know more conversions, but knowing a few basic ones will enable you to create others.

- Anonymous5 months ago
You'll just have to remember. But also keep in mind it's easier to remember there's about 1.6 km per mile.

- PuzzlingLv 75 months ago
You need to memorize common conversions factors, or at least be able to look them up. You can't really deduce a conversion factor otherwise.

But you can just ask Google...

Type "How many meters in a mile?" and you get 1609.

Ok that's what I was afraid of, having to remember more stuff. Ugh! Thanks. :)

Ok gotcha, thanks for the help! :)