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**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

Find the scale factor of each if the polygons are proportional

A = 7, 7, 21, 23 B = 28.7, 28.7, 86.1, 94.3

I choose A and I am still kind of confused because I divided 7/28.7 and got 0.2439024 in the calculator but when I did it I got 4.1

A Prop, s.f. = 0.244

B Prop, s.f. = 0.215

C Prop, s.f. = 0.284

D Prop, s.f. = 0.297

E Prop, s.f. = 0.236

F Prop, s.f. = 0.212

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 90,663

Hi;

I divided 7/28.7 and got 0.2439024 in the calculator but when I did it I got 4.1

You went backwards on that calculation with the calculator?

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,532

It just depends on whether you do (A divided by B) or (B divided by A).

If the second shape has got smaller you want a fraction for the scale factor and if it has got bigger you want a number over 1.

Yet it seems your course teachers have this back to front ???

No problem as long as the questions are consistent about this.

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

A = 7, 7, 21, 23 B = 28.7, 28.7, 86.1, 94.3

I got A as correct but like I rounded 0.2439 to 2440 is that a correct option? or is there another way to get the answer.

A Prop, s.f. = 0.244

B Prop, s.f. = 0.215

C Prop, s.f. = 0.284

D Prop, s.f. = 0.297

E Prop, s.f. = 0.236

F Prop, s.f. = 0.212

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 90,663

Hi;

That is what I got too. Did you check it?

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

28.7 x 0.244= 7.0028 so I ignore the 0028? right

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 90,663

Hi;

Not necessary.

.2439 can be rounded to .244. That is why I like A.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

I answered 5-D 8-D 9-E 10-B and they were all incorrect So I revised it and here is what I got wondering if it is correct

5. A because 9/41.4 gives me 0.2173913

but when I check it its wrong

5. A = 9, 10, 16, 19 B = 41.4, 46, 73.6, 87.4

A Prop, s.f. = 0.217

B Prop, s.f. = 0.318

C Prop, s.f. = 0.421

D Not prop

E Prop, s.f. = 0.294

F Prop, s.f. = 0.721

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**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

41.4 divided by 9 gives be 4.6 and when I check it it is correct why do they give us such weird decimal confusing numbers it confuses me and it gets annoying

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 90,663

I like D.

**In mathematics, you don't understand things. You just get used to them.**

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**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

me 2 but I got D as incorrect

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 90,663

What did they say the answer was? It really should be A.

**In mathematics, you don't understand things. You just get used to them.**

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,532

hi zee-f

Answer A is the correct answer.

If your teacher has a different answer on the markers sheet ask that it be corrected.

You may use the evidence below.

Bob

ps.

41.4 divided by 9 gives be 4.6 and when I check it it is correct why do they give us such weird decimal confusing numbers it confuses me and it gets annoying

Yes, you are right. If shape A is transformed into B using a scale factor the correct way to compute the sf is to calculate B/A.

I don't know why they have this back to front, but you can get their answers by doing A/B so it looks like you'll have to live with this. Just be prepared to do it properly when you meet scale factors elsewhere!

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

It turned out to be .217 as a correct answer

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 90,663

Kaboobly doo! Oh wait, I liked A too. Brilliant answer then.

**In mathematics, you don't understand things. You just get used to them.**

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