*HELP* math question!?

Question

ok. i'm currently failing math ....... over winter break my math teacher gave my a chance to bring it up .. so i ahve this worksheet i ahve to do. i'm really confussed with rotation symmetry. the definition in my book donsen't make sense to me!! could someone brifley explain rotation symmetry and give my an example??

thank you your answer is alot less complicated from the one in my horrible math book.

Answer 1

Hi,

Here is a website with pages you can look at to study symmetry. Choose Rotational Symmetry challenge 1 and work through the pages. I hope that will help you with visual aids!! :-)

Answer 2

Rotational Symmetry is basicly you have an object and you can turn it, at what angles and how many times does the object look the same, like a Square would have a rotational symmetry every 90 degrees (4) where as a square with 4 checks (black white/white black) would only have a rotational symmetry ever 180 degrees (2). I hate using wikipedia to explain things but it might do better than I can...

http://en.wikipedia.org/wiki/Rotational_symmetry

Answer 3

An object or figure has rotational symmetry if it looks the same if it is rotated through a certain angle.

For example if you have a square with center at (0,0), and the two diagonals drawn, and two opposite sides are parallel to the y-axis and the other two sides are parallel to the x-axis, then if you rotate the square about (0,0) 90 degrees it looks exactly the same as it did before you rotated it. In fact each rotation of 90 degrees makes the square look the same as its original position.

Answer 4

Cut out two squares of the same size. Draw the diagonals to find the centers where they intersect. Place one on top of the other and put a pin through them. Now, can you rotate the top square counterclockwise (or clockwise) until it exactly "fits" on top of the bottom square? Answer: yes, turn it 90 degrees. So the square has rotational symmetry for a 90 degree rotation since the square comes back to be in the same position. Someone who blinked would not know you had rotated the top square. You could draw the bottom square on paper and only cut out one square and do the same thing. Since the square, under rotation of 90 degrees comes back to fill the exaxt space it did before rotation we say it has rotational symmetry for 90 degrees. But I think you will discover it has rotational symmetry also for 180, 270 and 360 degrees. This is very important in quantum physics, design of tiles and wall paper, and many other fields.
Buyt wait. There are other ways to rotate, turn, and flip the square so it comes back to rest on top of the bottom square. For example flip the square about one of its diagonals.

Can you think of others. If you gave each of these symmetiresw names such as R1, R2, R3, R4, F!, F2, FV and FH (for a flip around a horizontal line through center of square, you would have things that acts like numbers, they can be combined into two symmetries that produce the same result as one of the others. You are inventing a completely new kind of math called Group Theory! In this case, the group of symmetries of a square.

Answer 5

If you cut out the shape and then stick a pin in it to attach it to a bulletin board, you could spin the shape.

It is said to have rotational symmetry if there is somewhere you could stop that would look EXACTLY the same as when you started to spin it WITHOUT having to go all the way around 360 degrees.


For example, if you spin a rectangle, you could turn it up-side-down, and it would look the same as when you started.
With a square, you can spin it 90 degrees and it looks the same as when you began.
A triangle that is either isosceles or scalene does not have rotational symmetry, but an equilateral triangle does -- if you start with one corner up, then you could stop when either of the other corners gets to that same spot.

I hope this helps!



You're welcome!

Answer 6

All it means is that you can rotate the object less than a full turn and get an identical view as you started with. An example is a plus sign. After 90 degrees of rotation, you have something that looks the same as the original.

A circle is the ultimate object for this in two dimensions, or a sphere in three dimmensions. No matter what direction you look at it, it looks the same.

Answer 7

A figure has rotational symmetry if, after turning
it about a point through an angle of less than 360
degrees, it becomes exactly the same figure.
Example: Take a square. Draw both its diagonals.
Use their point of intersection as a turn center.
Now rotate the square 90 degrees about this point.
You will get the same square!
Good luck with your maths course.

Answer 8

if you need to call me you can

Answer 9

I will explain it you in one example .

if you took a point in the graph like for example (-2;2).
The rotation symmetry is to do the symmetry of this point compared with x'x and y'y, so we will get in the (ox;yo) graph ( 2;2), and in the (ox';oy') we'll get (-2;-2). But there will remain also the 4th point of symmetry in the graph (ox;oy') which is (-2;2) . this is it . If you need more explanation we should see some of your exercises that you're taking in class so I can more explain and clearer .