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Author Topic: Try this  (Read 14340 times)

Offline Mince

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Try this
« on: March 05, 2007, 11:21:55 PM »
Work out the area of an equilateral triangle of sides 26.

I have a twelve-year-old who can do this.
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Offline Diane CBPFC

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Re: Try this
« Reply #1 on: March 06, 2007, 12:52:16 AM »
26 what?
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People will come from strange lands to hear me speak my words of wisdom. They will ask me the secret of life and I will tell them. Then maybe I'll finish off with a song. The Nomad

Offline The Peepmaster

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Re: Try this
« Reply #2 on: March 06, 2007, 06:34:05 AM »
Potatoes. I think he's showing off again. ::)
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Offline Mince

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Re: Try this
« Reply #3 on: March 06, 2007, 08:22:31 AM »
26 centimetres or 26 metres or 26 yards. The units are irrelevant.

I'm not showing off: she can do it, but I never said I could. I mean, okay, I can, but I didn't actually say I could.
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Offline Tarquin Thunderthighs lll

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Re: Try this
« Reply #4 on: March 06, 2007, 08:33:16 AM »
Er...338, I think. Surely every 12-year-old should be able to do that, or am I missing summat? Like a brain?
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Offline Mince

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Re: Try this
« Reply #5 on: March 06, 2007, 08:47:26 AM »
Is 338 rounded off?
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Offline Tarquin Thunderthighs lll

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Re: Try this
« Reply #6 on: March 06, 2007, 09:35:09 AM »
Er...no - it's just wrong.

BUT....I realise my mistake, and I shall be back.

Apologies to all 12-year-olds - it's not quite as simple as I thought, bleary-eyed, over my morning coffee. In my defence, it's been over 30 years since I last sat in a maths class.
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Offline Tarquin Thunderthighs lll

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Re: Try this
« Reply #7 on: March 06, 2007, 10:06:32 AM »
Okay, the most accurate answer I can come up with is 292.71658647914026260613843171449 square units, but 292.5 would be fair.

There is a formula you can use, but basically you're working backwards from Pythagoras Theory, establishing the height of the equilateral triangle by taking the square of one of the sides (26x26) and subtracting the square of half of one of the other sides (13x13), and calculating the square root of the answer to give you the 'height' (i.e. the length of the perpendicular from the base of the triangle to its apex, which evenly bisects the triangle). Once established, you then simply multiply that height by half the base to get the total area of the equilateral triangle. The formula is [where s = the length of one side] Area = (s squared x the square root of 3) divided by 4.

Don't know how I missed it this morning, but once again, I apologise if I may have mislead you all, and good work to your 12-year-old.
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Offline The Peepmaster

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Re: Try this
« Reply #8 on: March 06, 2007, 10:36:07 AM »


I think the answer's 27 cuttlefish.
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Offline Mince

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Re: Try this
« Reply #9 on: March 06, 2007, 10:41:43 AM »
LOL!

Well done, Tarquin. We're quite the mathematician.

Peepmaster, what on Earth is that? Are you still failing basic algebra?
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Offline Mince

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Re: Try this
« Reply #10 on: March 06, 2007, 10:49:41 AM »
Tarquin, try this one:

Four circles perfectly fit into one square. The shaded area is 16 (units squared). What is the area of the square?



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Offline Mince

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Re: Try this
« Reply #11 on: March 06, 2007, 10:53:39 AM »
And here is one more. Two cars are approaching each other head-on. One is travelling at a constant speed of 30mph and the other is travelling at a constant speed of 40mph. They begin 350 miles apart. A fly, sitting on the bumper of the first car at the beginning, flies at 60mph to the other car, and then turns round and flies back, and then continues to repeat flying back and forth between the cars until the cars crash and squash the fly. How far does the fly travel before it is squashed?
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Offline Tarquin Thunderthighs lll

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Re: Try this
« Reply #12 on: March 06, 2007, 11:34:06 AM »
Thankfully I have work to do now, but the answer to the first one is 16 plus [4 times (pi x circle radius squared)] units squared.

Regrettably, I haven't had time to apply any thinking to the second one, but I do know the last thing to go through the fly's head upon impact...
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Offline The Peepmaster

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Re: Try this
« Reply #13 on: March 06, 2007, 12:07:11 PM »
Quote from: Tarquin Thunderthighs lll on March 06, 2007, 11:34:06 AM
Thankfully I have work to do now, but the answer to the first one is 16 plus [4 times (pi x circle radius squared)] units squared.

Hmm - I think it's 32 units, with each unit being of similar size.
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Offline Mince

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Re: Try this
« Reply #14 on: March 06, 2007, 12:20:59 PM »
Quote from: Tarquin Thunderthighs lll on March 06, 2007, 11:34:06 AM
Thankfully I have work to do now, but the answer to the first one is 16 plus [4 times (pi x circle radius squared)] units squared.

There's just one problem. You don't know the radius.

The second problem is really easy.
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