Symmetry is the quality of being made up of exactly similar parts facing each other or around an axis.Watch SYMMETRY VIDEO to learn more.
Symmetry comes from a Greek word meaning ‘to measure together’ and is widely used in the study of geometry. Mathematically, symmetry means that one shape becomes exactly like another when you move it in some way: turn, flip or slide. For two objects to be symmetrical, they must be the same size and shape, with one object having a different orientation from the first. There can also be symmetry in one object, such as a face. If you draw a line of symmetry down the center of your face, you can see that the left side is a mirror image of the right side. Not all objects have symmetry; if an object is not symmetrical, it is called asymmetric.
When working with symmetry, the initial image is called the pre-image, and the second image is called theimage because it is the final step in the process. Just like the answer to a math problem is the final step in that process, the image is what is created when you rotate something 90 degrees or flip it about the x-axis. There are three basic types of symmetry: rotational symmetry, reflection symmetry and point symmetry.
The line of symmetry or Reflection symmetry divides the shape into two identical parts. The line can be vertical , horizontal or diagonal.
When a shape is rotated 1800 it looks the same or it looks same when turned upside down. If we take playing cards we see they have point symmetry as they are similar from bottom and top; and even if cut diagonally.
Useful for CBSE, ICSE, NCERT & International Students
Grade : 9
Subject : Maths
Lesson : Lines and Angles
Topic: SYMMETRY VIDEO
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