can you help please.

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bexamy
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Joined: Thu Jul 11, 2013 11:08 am

can you help please.

Post by bexamy »

Not being too good with maths I cannot help my daughter with this math question can anyone here please? Andrew is ordering a fence, in order to make 2 new adjoining fields for some sheep. He has 8750m sq to fence and has ordered 475m of fencing supplies. Andrew wants to make the smaller field exactly three quarters the size of the larger field, and needs them both to be rectangular. What dimensions should Andrew make the blocks?

My daughter had divided 8740 by 100 to get 87.5 to get a measurement of 100x87.5 for the field. She is then saying you would need 3 lengths of 100m and 2 of 87.5m dividing the field by placing 1 of the 100m lengths 21.875 of the way down the 87.5m side of the field. I am confused she is 10 and desperate for me to help her. Anyone able to help me please and simplify it?
ToadMum
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Location: Essex

Re: can you help please.

Post by ToadMum »

I think she is nearly but not quite there...

If the smaller field is to be three-quarters the size of the larger one, place the dividing fence four-sevenths of the way along the 87.5m side (using 'quarters' as units, you want one field to have its shorter sides measuring four of them and the other, three). You will then have one field 100m x 50m and the other 100m x 37.5m.

I hope this makes sense!
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bexamy
Posts: 57
Joined: Thu Jul 11, 2013 11:08 am

Re: can you help please.

Post by bexamy »

Sadly that makes no sense to me! She says that to make the smaller field exactly three quarters the size of the larger field would make the smaller field one quarter so she had divided 87.5 by 4 to get one quarter being 21.875 for smaller field to make that field 100x21.875 so larger field would be 3x21.875 = 65.625 so 65.625x100 for the large one. I don't understand the four sevenths bit. I am incredibly dense with math please be patient.
leanmeamum
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Joined: Sat Dec 03, 2011 4:14 pm

Re: can you help please.

Post by leanmeamum »

there are 4 quarters in a whole so 3/4 + 4/4 = 7/4

so you divide the field by 7 and give one portion 3 parts and the other portion 4 parts to make the smaller field 75% or 3/4 of the big field.
bexamy
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Joined: Thu Jul 11, 2013 11:08 am

Re: can you help please.

Post by bexamy »

:? Sorry I sort of get it but its trying to explain that last step to my daughter,
leanmeamum
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Joined: Sat Dec 03, 2011 4:14 pm

Re: can you help please.

Post by leanmeamum »

she has already worked out that the field is 100 X 87.5 m in dimension.

She has also worked out that you need 3 X 100 m lengths and 2 X 87.5 m of fence to make up the boundary plus the dividing line.

Now she needs to cut the field up in the ratios mentioned in the question. One part is 3/4 of the other so altogether you have 3/4 + 4/4 = 7/4 or 7 quraters. You cut the 87.5 into 7 parts and give the smaller field 3 parts and the bigger field 4 parts. If you imagine 3/4 as a % it is 75% of 100.

So 87.5 / 7 = 12.5 m so the smaller field will be 12.5 X 3 = 37.5 m wide and the big field will be 12.5 X 4 = 50 m wide

Therefore your 2 fields will be 37.5 X 100 and 50 X 100 in dimension.

Hope this helps
bexamy
Posts: 57
Joined: Thu Jul 11, 2013 11:08 am

Re: can you help please.

Post by bexamy »

Yes she understood it more than me, she said oh yeah, it says 3/4 the size of the larger field not 3/4 the size of the field. Thank you all for your help. I am sure I am going to need it very soon at this rate. Didn't think I would be struggling with primary school work lol.
Kingfisher
Posts: 416
Joined: Wed Sep 05, 2012 7:08 pm

Re: can you help please.

Post by Kingfisher »

bexamy wrote:Andrew is ordering a fence, in order to make 2 new adjoining fields for some sheep. He has 8750m sq to fence and has ordered 475m of fencing supplies. Andrew wants to make the smaller field exactly three quarters the size of the larger field, and needs them both to be rectangular. What dimensions should Andrew make the blocks?
Okay, so let's start by taking out the unnecessary parts of the question.
bexamy wrote: He has 8750m sq to fence and has ordered 475 m of fencing. Andrew wants to make the smaller field exactly three quarters the size of the larger field, and needs them both to be rectangular. What dimensions should Andrew make the blocks?
I suggest you draw it out.
We know the perimeter of the rectangle must be less than 475 m. For convenience's sake, let's make one side of the field 100 m. To get the other sides, we divide 8750 by 100 to get 87.5. So now we know the dimensions of the WHOLE are 100 x 87.5 m.

Add it all together (100+100+87.5+87.5) and you get 375. He ordered 475 m of fencing, so the other 100 m must be used to divide the field (draw a line through the rectangle)



However, we still don't know how it's divided, so let's look at the rest of the question.

We know that the smaller field must be 3 quarters the size of the larger one - 1 quarter smaller.

We know that one side of both fields will still be 100 m in length, so let's work out the other length.

There are 4 quarters in a whole, so the larger field (LF) must be 4 quarters in length. The smaller field (SF) would be 3 quarters in length. Overall this is 3 + 4 which is 7 'quarters'.

Now you must divide the other side (87.5 sq m) by seven which is 12.5. So one 'quarter' is 12.5.

LF's dimensions would be 100 x 50 (in other words 12.5 x 4) making the area 5000 sq m
SF's dimensions would be 100 x 37.5 (in other words 12.5 x 3) making the area 3750 sq m

Now let's check - 50 + 37.5 is 87.5, so that should be right.
5000+ 3750 is 8750 (the original area of the field), so that should also be right.

Hope I helped :)
Little Miss Kingfisher - Kingfishers 11 yr old daughter.
Kingfisher
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Joined: Wed Sep 05, 2012 7:08 pm

Re: can you help please.

Post by Kingfisher »

Aww you beat me to it leanmeamum
bexamy
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Joined: Thu Jul 11, 2013 11:08 am

Re: can you help please.

Post by bexamy »

Yes thank you she understands it now.
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