Math Is Fun Forum

mathland

Member

Registered: 2021-03-25

Posts: 444

3 Ways To Write Ratios

This is a silly question but I forgot how to do it.

For every 3 land iguanas in the Galapagos Islands, there are 5 marine iguanas. Write 3 equivalent ratios.

Let me see.

There are 3 ways to write ratios:

1. Words

3 to 5

2. Colon

3:5

3. Fraction

3/5

Is this right?

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 47,946

Re: 3 Ways To Write Ratios

In my opinion, yes. I think the first '3 is to 5' is also right.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,580

Re: 3 Ways To Write Ratios

hi mathland,

I'm not so sure.

Words and colon yes.  Sometimes a fraction works too but, for this example, I don't think it appropriate.  If you tell someone a ratio, you're trying to communicate the relative proportions.  Writing a fraction means [so many] out of [total] so the land fraction would be 3/8 and the marine fraction 5/8

Does this question mean find other ratios that are equivalent?

eg.  3:5 = 6:10 = 9:15

On this page https://www.mathsisfun.com/numbers/ratio.html MIF does use fractions as an alternative so maybe I'm wrong.

In the horse scaled example 1/10 is used and in that context it works ok.  So I'm not saying using fractions is always wrong; just not in the context of this question.

You could also use percentages 37.5% land and 62.5% marine.

In this U Tube clip
https://www.youtube.com/watch?v=IzeEHF2 … yg&index=1

fractions are used like this but the clip also says that the ratio of 4 inches to 32 feet is 4:32 which just goes to demonstrate that not everything on the internet is true.

Where did the question come from?  Maybe there's a clue in the pages that led up to this.

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

mathland

Member

Registered: 2021-03-25

Posts: 444

Re: 3 Ways To Write Ratios

hi mathland,

I'm not so sure.

Words and colon yes.  Sometimes a fraction works too but, for this example, I don't think it appropriate.  If you tell someone a ratio, you're trying to communicate the relative proportions.  Writing a fraction means [so many] out of [total] so the land fraction would be 3/8 and the marine fraction 5/8

Does this question mean find other ratios that are equivalent?

eg.  3:5 = 6:10 = 9:15

On this page https://www.mathsisfun.com/numbers/ratio.html MIF does use fractions as an alternative so maybe I'm wrong.

In the horse scaled example 1/10 is used and in that context it works ok.  So I'm not saying using fractions is always wrong; just not in the context of this question.

You could also use percentages 37.5% land and 62.5% marine.

In this U Tube clip
https://www.youtube.com/watch?v=IzeEHF2 … yg&index=1

fractions are used like this but the clip also says that the ratio of 4 inches to 32 feet is 4:32 which just goes to demonstrate that not everything on the internet is true.

Where did the question come from?  Maybe there's a clue in the pages that led up to this.

Bob

The words, colon and fraction is taught in several You Tube clips. This is where I got the information.

mathland

Member

Registered: 2021-03-25

Posts: 444

Re: 3 Ways To Write Ratios

hi mathland,

I'm not so sure.

Words and colon yes.  Sometimes a fraction works too but, for this example, I don't think it appropriate.  If you tell someone a ratio, you're trying to communicate the relative proportions.  Writing a fraction means [so many] out of [total] so the land fraction would be 3/8 and the marine fraction 5/8

Does this question mean find other ratios that are equivalent?

eg.  3:5 = 6:10 = 9:15

On this page https://www.mathsisfun.com/numbers/ratio.html MIF does use fractions as an alternative so maybe I'm wrong.

In the horse scaled example 1/10 is used and in that context it works ok.  So I'm not saying using fractions is always wrong; just not in the context of this question.

You could also use percentages 37.5% land and 62.5% marine.

In this U Tube clip
https://www.youtube.com/watch?v=IzeEHF2 … yg&index=1

fractions are used like this but the clip also says that the ratio of 4 inches to 32 feet is 4:32 which just goes to demonstrate that not everything on the internet is true.

Where did the question come from?  Maybe there's a clue in the pages that led up to this.

Bob

The words, colon and fraction is taught in several You Tube clips. This is where I got the information.

My nephew is in middle school. I help him out with math homework all the time but I haven't seen this ratio stuff in years.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,580

Re: 3 Ways To Write Ratios

Maths is supposed to allow us to model the real world.  And it should communicate usefully.  So I'm wary of using a fraction in this situation; that's all.  If your nephew follows my argument and agrees he could try telling his teacher.  Modern education encourages the child to think for themselves and to question things.  I, for one, would be impressed by a pupil who questioned the established usage.

A lesson that I had given many times involved every child drawing a triangle (any) and the measuring it's angles and adding them up. Then I asked for their results.  I regularly got answers ranging from 178 to 182 degrees.  That's to be expected because you cannot measure angles any better with a standard protractor.  Then I ask the class for a conclusion. For years we had all written down "The angles of a triangle add up to 180 degrees".  On one occasion a boy put his hand up and said "The angles of a triangle add up to roughly 180 degrees, sometimes a little more, sometimes a little more".  RESPECT!  I was most impressed.  Good answer and an interesting discussion followed.

When I had my University entry interview I was asked a question and I trotted out what I had been taught. The professors looked puzzled and asked if I agreed with what I had been taught.  I told them I didn't and then gave the correct result which I had reasoned out myself.  I learnt later that was why they decided to offer me a place.

Bob

---

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

mathland

Member

Registered: 2021-03-25

Posts: 444

Re: 3 Ways To Write Ratios

Maths is supposed to allow us to model the real world.  And it should communicate usefully.  So I'm wary of using a fraction in this situation; that's all.  If your nephew follows my argument and agrees he could try telling his teacher.  Modern education encourages the child to think for themselves and to question things.  I, for one, would be impressed by a pupil who questioned the established usage.

A lesson that I had given many times involved every child drawing a triangle (any) and the measuring it's angles and adding them up. Then I asked for their results.  I regularly got answers ranging from 178 to 182 degrees.  That's to be expected because you cannot measure angles any better with a standard protractor.  Then I ask the class for a conclusion. For years we had all written down "The angles of a triangle add up to 180 degrees".  On one occasion a boy put his hand up and said "The angles of a triangle add up to roughly 180 degrees, sometimes a little more, sometimes a little more".  RESPECT!  I was most impressed.  Good answer and an interesting discussion followed.

When I had my University entry interview I was asked a question and I trotted out what I had been taught. The professors looked puzzled and asked if I agreed with what I had been taught.  I told them I didn't and then gave the correct result which I had reasoned out myself.  I learnt later that was why they decided to offer me a place.

Bob

1. They asked you a math question during an interview. Really?

2. The sum of the angles in a Euclidean geometry triangle measure 180 degrees but not true for non- Euclidean geometry triangles. Yes?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,580

Re: 3 Ways To Write Ratios

it was a University interview for a place to study maths.  In the Uk, students who want to go straight from school, haven't yet done their final exams, so the Uni must try to assess suitability in other ways.  So it's likely a candidate will be asked maths questions.

The 180 rule does only work for flat surfaces.  You make a 'triangle' on the Earth's surface as follows.  'Side 1' is an arc along the equator from A to B.  At A 'side 2' is an arc along the line of latitude up to the North Pole (C).  'Side 3' goes along another line of latitude from B to C.

The angles are 90 90 and anything depending on how long you make AB.

Bob

---

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

mathland

Member

Registered: 2021-03-25

Posts: 444

Re: 3 Ways To Write Ratios

it was a University interview for a place to study maths.  In the Uk, students who want to go straight from school, haven't yet done their final exams, so the Uni must try to assess suitability in other ways.  So it's likely a candidate will be asked maths questions.

The 180 rule does only work for flat surfaces.  You make a 'triangle' on the Earth's surface as follows.  'Side 1' is an arc along the equator from A to B.  At A 'side 2' is an arc along the line of latitude up to the North Pole (C).  'Side 3' goes along another line of latitude from B to C.

The angles are 90 90 and anything depending on how long you make AB.

Bob

Interesting.  How much do you like Happy Days? Did you know that Henry Wrinkler took geometry several times and finally passed with a D. The Fonz feared the Pythagorean Theorem in real-life.  Did you know that?.