Math Is Fun Forum

Zeeshan 01

Member

Registered: 2016-07-22

Posts: 746

Ratios

Hi::
Read ratio topic in mif https://www.mathsisfun.com/numbers/ratio.html
Don't understand how to write in fraction There are 3 blue squares to 1 yellow square
It is given 3:1 but in fraction it say numerator And denominator numerator is part we have and denominor is the whole is divided into
Explain  this??

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Malik

Bob

Administrator

Registered: 2010-06-20

Posts: 10,640

Re: Ratios

denominator is the whole

The whole has 4 squares.

numerator is part we have

If you want the blue fraction that is 3 squares so blue fraction is 3/4

If you want the yellow fraction that is 1 square so yellow is 1/4

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Zeeshan 01

Member

Registered: 2016-07-22

Posts: 746

Re: Ratios

So what is 3÷1

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Malik

Monox D. I-Fly

Member

From: Indonesia

Registered: 2015-12-02

Posts: 2,000

Re: Ratios

It shows that there are 3 blue squares for each 1 yellow square

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Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.

Zeeshan 01

Member

Registered: 2016-07-22

Posts: 746

Re: Ratios

I don't think it says this

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Malik

Bob

Administrator

Registered: 2010-06-20

Posts: 10,640

Re: Ratios

So what is 3÷1

This reads as 'three divided by one'  Did you mean that, or did you intend to type 3:1   ?

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

iamaditya

Member

From: Planet Mars

Registered: 2016-11-15

Posts: 821

Re: Ratios

I don't think it says this

Yes, it says that only.

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There is no substitute to hard work
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Zeeshan 01

Member

Registered: 2016-07-22

Posts: 746

Re: Ratios

3:1 and 3÷1 are not same things>>>

Last edited by Zeeshan 01 (2017-07-27 00:10:13)

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Malik

Bob

Administrator

Registered: 2010-06-20

Posts: 10,640

Re: Ratios

Sorry, Zeeshan 01, but what I'm seeing  are not the same.

I'm seeing a divide symbol and a colon.  A colon is commonly used to indicate a ratio.  Ratio and division(fraction) are not the same, although they are closely and simply connected.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Zeeshan 01

Member

Registered: 2016-07-22

Posts: 746

Re: Ratios

there is no compound proportion topic to express how to treat different information how to reverse order and other things
>>>

Last edited by Zeeshan 01 (2017-07-27 00:08:20)

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Malik

Bob

Administrator

Registered: 2010-06-20

Posts: 10,640

Re: Ratios

hi Zeeshan 01

You were asking about ratio and fractions and now you have jumped to compound proportion.

May I assume you are ok now with ratio and fractions?

Before you jump to compound proportion, are you ok with simple proportion, both direct and inverse?

Easier if you have an example.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Zeeshan 01

Member

Registered: 2016-07-22

Posts: 746

Re: Ratios

No I am not asking about fraction only ratio and proportion topics

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Malik

Zeeshan 01

Member

Registered: 2016-07-22

Posts: 746

Re: Ratios

Yes ok with those two!!!!!

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Malik

Bob

Administrator

Registered: 2010-06-20

Posts: 10,640

Re: Ratios

I had a look at other on-line sites for compound proportion.  There are formulas but I wouldn't recommend trying to learn and use them.  Compound proportion means a series of simple proportion steps, so you can always do a problem by considering each step separately.  Here's a example to show what I mean:

example.   A fence company employs people to dig the post holes.  There are three variables:

How many people to dig the holes.
How much time they will take.
How many holes are needed.

If the number of holes is fixed, then more people means less time to dig, so that is inverse proportion.
If the number of people is fixed, then more holes will take more time, so that is direct proportion.
If the amount of time available if fixed, then more people means more holes, so that is direct proportion.

Suppose we known that 10 people can dig 18 holes in 5 hours.

How long will it take for 15 people, to dig 12 holes ?

Let's keep the number of holes fixed first.  How long will 15 people take to dig 18 holes?

Holes fixed is inverse proportion. The number of people has gone up from 10 to 15, ie  times 15/10, so the time will go down by times 10/15

New time = 5 x 10/15 = 10/3 hours.

Now we'll keep the number of people fixed.  How long will 15 people take to dig 12 holes ?

People fixed is direct proportion.  The number of holes has gone from 18 to 12 ie. times 12/18, so the time will go down by times 12/18

New time = 10/3 x 12/18  = 10/3 x 2/3 = 20/9 hours.

Hope that helps.

If you really want the formulas, 'google' compound proportion and you'll find lots of sites.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Zeeshan 01

Member

Registered: 2016-07-22

Posts: 746

Re: Ratios

I had a look at other on-line sites for compound proportion..

Do you don't know this

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Malik

Zeeshan 01

Member

Registered: 2016-07-22

Posts: 746

Re: Ratios

but my question is why we reverse order in inverse proportion can you show me with example

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Malik

zetafunc

Moderator

Registered: 2014-05-21

Posts: 2,440

Website

Re: Ratios

Here is a nice example: http://www.bbc.co.uk/schools/gcsebitesi … rev2.shtml