BS: Perfect American Pi Day

Subject: BS: Perfect American Pi Day
From: Mrrzy
Date: 13 Mar 15 - 11:31 PM

Once a century... and only in the US. Saturday this week just before 9:30 in the morning in America it will be:

3.14.15@9.26.5358979323846.........

Subject: RE: BS: Perfect American Pi Day
From: GUEST,Eta the Jay Pye
Date: 14 Mar 15 - 07:45 AM

DID YOU KNOW that (9*9 + 19*19/200)^0.25 is a good approximation to pi?

2 pi r, Lord,
2 pi r,
2 pi r, Lord,
2 pi r,
2 pi r, Lord,
2 pi r,
O Lord 2 pi r

Subject: RE: BS: Perfect American Pi Day
From: DMcG
Date: 14 Mar 15 - 08:16 AM

Now I - even I, would celebrate
In Rhymes unapt the great
Immortal Syracusan rivalled never more,
Who in his wonderous lore
Passed on before,
Left men his guidance
How to circles mensurate

Subject: RE: BS: Perfect American Pi Day
From: GUEST
Date: 14 Mar 15 - 08:50 AM

DID YOU KNOW that (9*9 + 19*19/22)^0.25 is a good approximation to pi?

Subject: RE: BS: Perfect American Pi Day
From: Manitas_at_home
Date: 14 Mar 15 - 01:35 PM

We could have 22nd July (22/7) every year.

Subject: RE: BS: Perfect American Pi Day
From: GUEST,punkfolkroker
Date: 14 Mar 15 - 02:13 PM

.. and as a good a time as any to praise the near perfect American Fuzz Box

- the classic " electro-harmonix Big Muff π "....

Subject: RE: BS: Perfect American Pi Day
From: Mrrzy
Date: 14 Mar 15 - 03:05 PM

Luckily Americans also do time wrong! since I misremembered it and celebrated this morning at 9:23:56 etc instead of 9:26:53 etc, I get to try again tonight, at 9:26:53 etc pm! It isn't, after all, zero nine...

Subject: RE: BS: Perfect American Pi Day
From: Airymouse
Date: 14 Mar 15 - 03:18 PM

In honor of the occasion, a maths problem:
A 3 foot by 5 foot rectangular flower bed is surrounded on its edges by a border of petunias of uniform width 1 foot. In square feet, what is the area of the border of petunias?

Subject: RE: BS: Perfect American Pi Day
From: michaelr
Date: 14 Mar 15 - 03:33 PM

20

Subject: RE: BS: Perfect American Pi Day
From: GUEST,Hi oo
Date: 14 Mar 15 - 03:39 PM

Kate bush sings Pi on her album Ariel. Lovely song!

Subject: RE: BS: Perfect American Pi Day
From: Nigel Parsons
Date: 14 Mar 15 - 05:19 PM

In honor of the occasion, a maths problem:
A 3 foot by 5 foot rectangular flower bed is surrounded on its edges by a border of petunias of uniform width 1 foot. In square feet, what is the area of the border of petunias?
9 (not the previously stated 20)

Of course, elsewhere that US we could celebrate Pi Day on 31 April (if only April had 31 days)
As it is we'll have to wait for 3 January '41 @ 5:9:26

Subject: RE: BS: Perfect American Pi Day
From: EBarnacle
Date: 14 Mar 15 - 09:03 PM

I just checked with the botanical garden--there are no one foot wide petunias.

Sorry, Nigel, 20 is correct. A rectangle has 4 sides and corner blocs.

Subject: RE: BS: Perfect American Pi Day
From: GUEST,Dmcg
Date: 15 Mar 15 - 03:52 AM

The question is ambiguous, to the extent that it is not absolutely definite whether the petunias are inside or outside the 3x5 area. In either case the area is the difference between the area-including-petunias and the area excluding petunias. So if it outside, the answer is 5x7 - 3x5, or 4x5 ie 20. Or if it is inside the area it is 3x5 - 1x3 ie 12.

Subject: RE: BS: Perfect American Pi Day
From: GUEST
Date: 15 Mar 15 - 04:17 AM

Let me ramble away a bit on thie petunia problem, because I think it gives an insight between the difference between what mathematics is and what schools call maths but is actually either arithmetic or perhaps a little beyond that. The "arithmetic" way of solving the problem is to perhaps draw a little sketch, see that there are four corners, and four strips each one foot wide and the length of one of sides, work out all the bits and add them together. That works, but, as mathematicians like to say, lacks generality. Suppose we had the same situation, but instead of it being a nice one foot border all of the way round, we rotated the inner rectangle so the centres of the larger and smaller rectangles coincided, but the corners of the inner touched the sides of the outer. Now the person who is following the arithmetic all approach schools teach finds themselves in a nightmare set of calculations: where exactly to the touch? What is the angle? What is the area of each of the triangles? .. And so on, all of which is is unnecessary, since all that is needed is to to observe that the area of the petunias is the total area minus the area that is not petunia, and position, orientation, where lines meet and all the rest is of no importance.

And that's why I don't think many schools teach mathematics.


And as a further generalisation in honour of pi day let me express Pythagoras theorem in an unconventional way: the circle on the hypotenuse is equal to the sum of the circles on the other two sides.

Subject: RE: BS: Perfect American Pi Day
From: GUEST,Dmcg
Date: 15 Mar 15 - 04:18 AM

Me again, above. I expect you guessed.

Subject: RE: BS: Perfect American Pi Day
From: EBarnacle
Date: 15 Mar 15 - 07:44 AM

Actually, because of rounding, next March 14 is also pi day, just not to as many places.

Subject: RE: BS: Perfect American Pi Day
From: Airymouse
Date: 15 Mar 15 - 07:58 AM

I like Guest's statement of the conclusion of the Pythagorean Theorem though I suggest a modification: The area of the circle on the hypotenuse is equal to the sum of the areas of the circles on the other two sides.
My problem is unfair and if I were grading it I would give full credit for the answer, 20. But I would give extra credit for the right answer, though I would expect people who lived on farms would have a huge advantage. Those folks have swung open fence gates and plowed fields and so they have a better chance of really thinking about what "uniform width" means. In my defence, I did say that the problem was posed in honor of Pi day, so you'd expect the answer to have Pi in it.

Subject: RE: BS: Perfect American Pi Day
From: GUEST
Date: 15 Mar 15 - 05:18 PM

alas we don't have fourteen months this side of the pond

Subject: RE: BS: Perfect American Pi Day
From: Mrrzy
Date: 15 Mar 15 - 05:39 PM

Every year has a Pi day (3.14) if you do your dates in American.

I actually forgot I was on 24-hour time so my screen shot read 21 where the correct digit is 9, and by the time I realized I could change my timezone I had to go all the way to Mountain Time. Sigh.

Also I made pie, which was oddly enough perfect on the inside (wonderfully flavored and didn't run all over when the pie was cut) but the crusts, shall we say, were neither light nor fluffy. They didn't fall apart, though, you could serve a slice of pie and it had both crusts and all its filling. And was yummy. Just, shall we say, chewy.

I love how *human* appreciation for this particular holiday on this particular year is. African elephants and dolphins probably have months, and they may have years, but I doubt they have centuries, and I doubt very seriously they have Pi to more than 10, decimal, places.

Subject: RE: BS: Perfect American Pi Day
From: Nigel Parsons
Date: 15 Mar 15 - 09:00 PM

Ah, right!
mea culpa
The original bed is 3ft*5ft = 15sq ft
The bed, including border is 3ft (plus 1ft each side)= 5ft * 5ft (plus 1ft each side) = 7ft. so 5*7 = 35, minus the inner bed of 15 = 20.

Subject: RE: BS: Perfect American Pi Day
From: GUEST,Mysha
Date: 16 Mar 15 - 09:22 AM

Hi,

I don't think the answer is all that nice and natural. Obviously, the petunias can't be part of the bed, since a border can't be of uniform width then for having to fill the corners. So, the border must be on the outside, which gives us four edges, of two different lengths, plus the corners which together form a full circle of 1 feet radius.

In all, I get 16+pi square feet of petunias, which fortunately matches the topic of this thread.

Bye,
                                                                Mysha

Subject: RE: BS: Perfect American Pi Day
From: Mrrzy
Date: 16 Mar 15 - 12:03 PM

Plus we get 9 am and 9 pm because americans can't count to 24, let alone remember what month it is. Whew. What with the time zones the US got 10 exact Pi times...

Subject: RE: BS: Perfect American Pi Day
From: Airymouse
Date: 16 Mar 15 - 08:38 PM

Hi Guest Mysha A++ Right answer and your explanation is spot on. I guess everyone has had his fill of my problem, but that's OK, because we won't have another perfect pi day in my lifetime.