Monday, November 29, 2010

Concave and Convex Polygons

Work in the following math link and leave a comment explaining one of your discoveries about convex and concave polygons. If you didn't make any learning discoveries, keep digging (asking question and searching for answers), until you do.

http://www.mathopenref.com/polygonconcave.html

15 comments:

  1. convex and concave are in every thing today from cars to food and so on. also the concave is proven to be more popular than convex. also my house is concave. so that is extra info

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  2. I just kept clicking more sides and if you have a regular shape that has
    20 side= 162 degrees
    40 side= 171 degrees
    55 side= 173 degrees
    65 side= 174 degrees
    99 side= 176 degrees

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  3. Do you know how you asked is if all regular polygons are convex in class? Well I found out the answer. It was exactaly what I expected! All regular polygons are convex!

    I know this because I kept on adding sides after turning it regular until it reached its' max amount of sides. After each side was added, I tried to make one verticy move into the midle of the shape. I couldn't while the shape was regular!

    I belive this happens because if you move a verticy to the middle of a shape, it changes the line lenght, and the angle measure. Once that happens, the shape is no longer regular, since the the two lines, and the one angle, are different lenghts, and measures than the rest. That is why all regular shapes are convex.

    I also found out that a concave shape can look like pac-man!

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  4. I learned that you can make any shape into a convex or concave shape. This is a very fun link too.

    Rhino

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  5. When I was reading the math concave or convex thingymajig I was learning alot of more facts that I kind of had not thought about or had not thought about in such detail and the documents really helped me
    Thank You Mrs. H

    A Pirate

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  6. I only didn't know how to make an entire shape with convex or cancave anlges, but thats not what they are. I understand.

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  7. I learned some stuff about convex and concave shapes,like that concave shapes have one or more interior angles that are greater than 180° and that convex shapes have all its interior angles less than 180°. But I am still lost and confused, but I get the main point.(Sort of)

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  8. I learned what convex and concave shapes actully are

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  9. this has taught me that to be a concave shape one or more angles have to be greater then 180 degrees.

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  10. A convex shape is a polygon where all vertices measure under 180 degrees. A concave shape is a polygon with at least one vertex measuring over 180 degrees. If you increase the number of sides infinitely, a concave polygon will get close to a circle.

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  11. I did not know the difference between a convex and concave polygon. I had assumed that one of that it had something to do with the vertices, but I wasn't sure. You know how some people can tell the difference between convex and concave by looking at concave as a cave? If you are talking about the differences between concave and convex, wouldn't it be hard to say that one caves in? Both cave in, depending on where you see the cave. I'm interested in learning how that program and things like it like Geometer's Sketchpad work. How do they allow you to move things around? I also found a great tutoring site called Tutor Vista. Go to Google and search it up. They help you in Math. You type back and forth to eachother. If you buy a membership, you can get sound too. Why can't a regular polygon be a concave shape? Hmm... time to put my deerstalker hat on and put on Mission Impossible. I will find out more.

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  12. I looked at all of the sides on regular and irregular polygons. All of the regular polygons are convex polygons and all of the irregular polygons are concave, except for 2..... the ones with five and four sides are convex. It is impossible to make a shape that is concave with 5/4 sides. Looking at this, I also learned what concave and convex shapes are. I know I had heard the words before, and as soon as I found out, I realized I knew it! This site is really usefull, for me!

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  13. I learned that All polygons are convex because when you go on the math link, make the shape regular and keep increasing the number of angles they will not change from convex to concave unless you pull a angle inwards. Also I learned that a concave shape in less than 180 degrees and a convex shape is more than 180 degrees. (A soccer ball is convex!)

    :)

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  14. I think you mean that all REGULAR polygons are convex.

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  15. I learned what convex and concave angles are.

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