Lines of Symmetry

This chapter explores lines of symmetry. It explores reflecting shapes, understanding reflective symmetry, and recognising shapes with reflective symmetry. No prior knowledge is required for this chapter.
Most shapes in the world have a line of symmetry. The shape shown below is a rectangle.
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Rectangles have lines of symmetry. Below the shape has been separated in half using a line of symmetry which is the dotted line.
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There is also another line of symmetry which we can place on the rectangle. The line of symmetry is shown below.
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While a rectangle has two lines of symmetry a square has 4 lines of symmetry. These lines of symmetry have been shown on the square below.
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Reflecting vertically

Now let’s explore reflecting shapes in a vertical line.
Whenever you look in the mirror and see a reflection of yourself the image that you see is as far into the mirror as you’re away from the mirror. This simple idea can help us in studying reflective symmetry.
Suppose we wanted to reflect the following pattern about the vertical red line.
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To simplify the process we reflect it square by square. You count the number of spaces the square is away from the line and do the same to the reflection side. It needs to be the same distance.
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First we reflect the first square using the steps described above.
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Then reflect another square.
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We go through the same steps until all the squares are on the other side.
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Reflecting diagonally

In this section we shall look at the diagonal line of reflection.
Reflecting diagonally can be more complex than what we’ve explored above for example;
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To make the reflecting process simply make the line of symmetry vertical as shown below.
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Then count the number of spaces the squares is away from the line, for example the first square below is 1½ spaces away.
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Do the same for the rest of the squares as shown below.
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