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Maths problem - help!

(31 Posts)
Mishap Wed 14-May-14 10:07:46

My DD is constructing a mandala which needs to have 120 individual (equal-sized) circles within a 3 metre diameter circle. I have found on the net an illustration of an arrangement of the circles that fits, but it does not say what size these small circles need to be.

Any maths wizards out there!!??

Sorry to tax your brains on this lovely sunny day.

rosesarered Wed 14-May-14 10:22:09

errr. 40mm?

rosesarered Wed 14-May-14 10:24:48

That's what came to mind but doubt very much it will be right.

rosesarered Wed 14-May-14 10:28:34

sorry! meant 140mm not 40.

Roderick Wed 14-May-14 16:58:36

Yes about 140 or 137 to be exact

Roderick Wed 14-May-14 16:58:37

Yes about 140 or 137 to be exact

Roderick Wed 14-May-14 16:58:37

Yes about 140 or 137 to be exact

Roderick Wed 14-May-14 16:58:39

Yes about 140 or 137 to be exact

Roderick Wed 14-May-14 16:58:39

Yes about 140 or 137 to be exact

Roderick Wed 14-May-14 16:58:39

Yes about 140 or 137 to be exact

Roderick Wed 14-May-14 16:58:39

Yes about 140 or 137 to be exact

Roderick Wed 14-May-14 16:58:39

Yes about 140 or 137 to be exact

JessM Wed 14-May-14 17:37:01

do they overlap?

Brendawymms Wed 14-May-14 17:58:10

My picture in my mind of a mandala would have a circle touching the outer circle at every three degrees but what do I know!

Anne58 Wed 14-May-14 18:00:59

Roderick take your finger off that button immediately!

Ana Wed 14-May-14 18:33:58

If they overlapped, Jess, that would be a whole new ballgame! grin

Mishap Wed 14-May-14 18:41:02

No - they do not overlap; and there needs to be a small space between each. I have come to the conclusion that circles of about 20cm would fit the bill.

As they say in a GCSE exam, could you please show your working Roderick.

Ana Wed 14-May-14 18:49:23

(But not necessarily x 8!)

grumppa Wed 14-May-14 18:54:40

120 circles with a radius of 137mm. would have a total area equal to that of the proposed circle containing them, but thus makes no allowance for the spaces between the small circles, so they would have to be significantly smaller.

Hmm.

Anne58 Wed 14-May-14 18:58:06

As evry fule nose, the answer is ...........42.

grumppa Wed 14-May-14 19:10:47

Of course, phoenix! But 42 what? Are zaphods a useful unit of measurement in this context?

MiceElf Wed 14-May-14 19:23:08

Just had sight of the KS2 Maths paper for 10/11 year olds

n stands for a whole number

2n is greater than 30
5n is less than 100

Write all numbers that n stands for

I wonder how many adults could tackle that one with ease?

Mamie Wed 14-May-14 19:36:27

My GD has been doing her KS2 maths today. I think she thought the mental maths paper was hard, but the second paper was OK.

annodomini Wed 14-May-14 19:46:46

My GD is also doing SATs this week. I think today is the last of them.

Ana Wed 14-May-14 19:48:15

I found that question easy.