Bad maths in the supermarket

Originally posted by nishwater on flickr with the following comment:

"At first glance you'd be forgiven for thinking that this is cheaper than the £23/kg parmesan sat next to it on the shelf "

What intrigues me is how the price per kilogram shown happened in the first place.

Fieldfares count Fibonacci

Two years ago it started with one fieldfare eating the apple windfalls outside my office.

It frequently had run-ins with a blackbird and so after a while it called in another fieldfare for support.

The blackbird was still hassling them however.

Next year a third fieldfare was called in and the blackbird responded by calling in some mates to help defend the winter food supply.

This year started with five fieldfares, and at the beginning of this recent cold snap there were a few more - three more in fact.

I am now looking out and can count exactly thirteen fieldfares engaged alternately in  feeding frenzy and bird wars with the increasing flock of blackbirds.

If I am not mistaken there should be 21 fieldfares tomorrow...

Has anyone got any spare windfalls?

To The Times, radius = diameter

Oh dear. Further (weak) coverage of the bicycle with Reuleaux polygon wheels.

The Times begins well by explaining the principles previously touched
on here but then goes on to expose it's correspondent's belief that
the radius is the same as the diameter. That is to say, since the
diameter of a Reuleaux polygon is constant then so must be the radius
but of course this not the case. The axle of a Reuleaux polygonal
wheel will rise and fall with it's forward progress.

Furthermore, if, as in this case, the front wheel is a Reuleaux
pentagon and the rear a Reuleuax triangle, the bobbing up and down
effect will be inconstant. Very uncomfortable if not nauseating.

http://technology.timesonline.co.uk/tol/news/tech_and_web/article6366308.ece

It's a Rouleaux Triangle/Pentagon etc

It has been pointed out to me that the answer to the question in my
last post is that we are talking about Reuleaux polygons. These are a
curve of constant width - that is, a curve such that, if two parallel
lines are drawn tangent to the curve, the distance between them does
not depend on their orientation.

Well, that's what Wikipedia says anyway:
http://en.wikipedia.org/wiki/Reuleaux_triangle

And this is confirmed by Wolfram Mathworld with a bit more technical
stuff: http://mathworld.wolfram.com/ReuleauxTriangle.html

I had forgotten about the rotary combustion engine which makes use of
the properties of such polygons:
http://auto.howstuffworks.com/rotary-engine2.htm

Thank you to Lyndon Baker for the original pointer to these resources.

What's do you call the shape of a UK 50p piece?

Can someone remind me what you call the sort of heptagon-type shape that is the UK 50p coin?

The reason I ask? I caught this news item at Ananova about Guan Baihua, 50, a retired military officer in Qingdao, who spent 18 months developing his unique bike.

"The front wheel is a five-sided pentagon while the back wheel is a triangle, reports the Bandao City Daily." says the news item and worse still, despite the obvious curved nature of the edges, Harshpaul at http://www.automotto.org/entry/man-gets-patent-for-odd-sided-wheels-bicycle/ says "A bicycle that has straight-edged wheels doesn't sound a very smart idea".

What I do know is that the curved sides are created as a section of a circle with its centre being the diametrically opposite corner. The effect being that the diameter of the shape remains the same, so to speak, thus allowing coins of this shape to roll through a coin-operated machine's internal workings just as easily as a circular coin. A cylinder (prism?) with such a cross-section will work perfectly as a roller. However, if the load is suspended on a central axle the effect can only be uncomfortable in a bike. All the more so with a five-sided front wheel and a three-sided rear wheel.

Anyway, the question was...what is the a curved-edged polygon thingy called?

Australian politician grows 2.7 metres taller

An Australian politician has had her legs lengthened according to
Ananova, an online news provider, . She is now over 4 metres tall
which should provide her with a dominating political presence in the
Logan city council chamber.

Fed up with what she saw as her diminutive height of 1.52m she paid a
Russian clinic to break her legs in four places and had them stretched
by "1mm a day for nine months". As a result, then, she is now 4.2
metres tall.

"Ms Ban was taunted at school and feared her height would damage her
credibility as she entered the legal profession and later went into
local politics." I reckon it's not her credibility that is damaged but
the basic mathematics of the journalist(s) involved.

You can read the full story here:
http://www.ananova.com/news/story/sm_3303713.html

I am so seriously under-weight...

According to a report in the UK Daily Mirror...

...I am so seriously under-weight that I am amazed I am still alive.

http://www.mirror.co.uk/life-style/dieting/2009/04/22/could-this-pill-really-be-the-diet-miracle-we-ve-been-waiting-for-115875-21295493/

In a report about this new diet medication the journalist tells us
that the pill is only available to those with a body mass index of 28
or more.

To check whether I qualified, I used their formula as published and my
Body Mass Index works out at 0.037.

Using the same algorithm I calculate that in order to qualify for the
pill I would either have to weigh 110g or be 49m tall.

Try the formula yourself:

BMI is a system used to determine how healthy your weight is in
relation to your height. Here's how to work out yours:

1 Measure your height in metres and multiply the figure by itself.

2 Measure your weight in kilos

3 Divide the weight by the answer to no.1

If you qualify for the diet pill with BMI of 28 or over using this
algorithm, then do let me know!