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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,654

This looks simple, but took over a week (part time), because every one has a different algorithm to make it work.

Have a play and tell me any problems or ideas. Thanks.

*Last edited by MathsIsFun (2006-11-29 09:55:11)*

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

Ooh, very fun. I like it a lot, for the most part.

One suggestion is that you could possibly put a 'Quadrilateral' button on, so that it lets you move the corners around freely, like you could before you click on any of the shape names. I realise that you can do that by clicking on the name that you currently have again, but it took me a while to figure that out.

Also, sometimes the transformations of the shape are a bit counter-intuitive. I move a point and the shape enlarges along one of the axes, then I move it a bit more and it suddenly starts rotating. I'm not sure how that could be fixed, but it was sometimes a bit confusing.

Ooh, and you might want to maybe say that the trapezoid is also known as a trapezium. I'm not sure where you could fit that in though. Maybe add it to the "one pair of parallel sides" description.

Overall though, a very good educational tool, particularly how it shows the properties of all the different quadrilaterals like that. I'm off to have another play.

Edit: Sometimes when you make a big shape and you then click on one of the other words, then some of the points go offscreen and it can be quite difficult to get them back on. Also, see the attached image.

Edit2: I figured out how to replicate the problem I got, and consequently had a bit of fun, with the 1st image being the result. (They're shown in reverse order of the order you upload them, for some reason) The problem happens if you try to move the points too quickly.

Why did the vector cross the road?

It wanted to be normal.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,654

Great feedback!

I can solve the "point moving too fast" thing.

For each shape I wanted it to be able to rotate. Most textbooks etc show the quadrilateral "unrotated" (example: the trapezoid always has its parallel sides horizontal). So I wanted to be able to show it in different "poses". I may not have selected the right way to move things, though. Can you give specific cases that are counter-intuitive? Maybe I can think of another way.

Also, if you select another shape, the points return to within the drawing area.

US: Trapezoid / UK: Trapezium is a big problem, which is just gonna stay that way till education authorities wake up. I put a note on it.

BTW: should it be called "Animation" or "Interactive"?

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**rida****Real Member**- Registered: 2006-09-25
- Posts: 839

it's exellent

Dreams don't come true, you gotta make them come true.

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

I vote for interactive. Animated suggests you just sit there and watch them move.

I found an example of the counter-intuivity. Let's say you have a rectangle ABCD with A in the top-left corner and B in the top-right. If I drag point A horizontally, then the rectangle stretches horizontally. But if I drag it vertically, then the rectangle rotates, which is confusing. And the same goes for all the other points. It might be better to make A and C always change the scale of it and B and D always rotate, although I'm not certain. There are lots of other similar situations to that. It's only a minor quibble though, it's still easy enough to use.

Another fault I found is that if I turn the diagonals on then it highlights line AD as well as the 2 actual diagonals. Also, it won't let me make a kite that has a reflex angle, even though they're perfectly fine quadrilaterals.

I was also going to suggest that you showed that squares were rectangles, like you showed that various things were parallelograms, but then I realised that squares were also rhombuses (rhombi?) and so you'd also have to show that somehow and that would just complicate things.

Why did the vector cross the road?

It wanted to be normal.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,654

I guess I called it "Animated" because the general term is "Animation". I have changed it to "Interactive" (including changing name of file so I will amend my first post).

I shall have to think about how to move the points ... do other members have comments?

I put a comment about the rotation on the page too.

Diagonals: fixed. Thanks.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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