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How Does Reflection Over a Line Change the Coordinates of a Shape?

When we talk about reflection in math, we’re looking at how a shape flips over a line. This line is called the line of reflection. Let’s make this easier to understand!

What is Reflection?

Think about a shape on a graph, like a triangle with corners at points A(1, 2), B(3, 4), and C(5, 2). If we reflect this triangle over a line, such as the x-axis (the horizontal line) or the y-axis (the vertical line), we need to see how each corner of the triangle flips. This flipping isn’t just random; it’s done in a specific way based on where the line is.

Reflecting Over the x-axis

When we reflect over the x-axis, the rule is simple: the x-coordinates stay the same, but the y-coordinates change to their opposite. Here’s how it works:

  • A(1, 2) becomes A'(1, -2)
  • B(3, 4) becomes B'(3, -4)
  • C(5, 2) becomes C'(5, -2)

So after flipping it over the x-axis, our new triangle is at points A'(1, -2), B'(3, -4), and C'(5, -2). Notice how the triangle flips down below the x-axis but keeps the same distance from the line.

Reflecting Over the y-axis

Now, if we reflect the same triangle over the y-axis, the process changes a bit. Here, the y-coordinates stay the same, while the x-coordinates change to their opposite. This gives us:

  • A(1, 2) becomes A'(-1, 2)
  • B(3, 4) becomes B'(-3, 4)
  • C(5, 2) becomes C'(-5, 2)

So after flipping over the y-axis, our triangle is now at points A'(-1, 2), B'(-3, 4), and C'(-5, 2). This puts it in a different part of the graph.

Reflecting Over the Line y = x

What happens if we reflect over a line that isn’t one of the axes, like the line y = x? In this case, we swap the x and y positions for each point:

  • A(1, 2) becomes A'(2, 1)
  • B(3, 4) becomes B'(4, 3)
  • C(5, 2) becomes C'(2, 5)

Important Points to Remember

  1. For the x-axis: A(x, y) becomes A'(x, -y).
  2. For the y-axis: A(x, y) becomes A'(-x, y).
  3. For the line y = x: A(x, y) becomes A'(y, x).

In summary, with reflection, you’re flipping a shape over a line. The way the coordinates change gives you a new position that mirrors the original one. The more you practice this, the easier it will be, and before long, flipping shapes will feel natural!

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How Does Reflection Over a Line Change the Coordinates of a Shape?

When we talk about reflection in math, we’re looking at how a shape flips over a line. This line is called the line of reflection. Let’s make this easier to understand!

What is Reflection?

Think about a shape on a graph, like a triangle with corners at points A(1, 2), B(3, 4), and C(5, 2). If we reflect this triangle over a line, such as the x-axis (the horizontal line) or the y-axis (the vertical line), we need to see how each corner of the triangle flips. This flipping isn’t just random; it’s done in a specific way based on where the line is.

Reflecting Over the x-axis

When we reflect over the x-axis, the rule is simple: the x-coordinates stay the same, but the y-coordinates change to their opposite. Here’s how it works:

  • A(1, 2) becomes A'(1, -2)
  • B(3, 4) becomes B'(3, -4)
  • C(5, 2) becomes C'(5, -2)

So after flipping it over the x-axis, our new triangle is at points A'(1, -2), B'(3, -4), and C'(5, -2). Notice how the triangle flips down below the x-axis but keeps the same distance from the line.

Reflecting Over the y-axis

Now, if we reflect the same triangle over the y-axis, the process changes a bit. Here, the y-coordinates stay the same, while the x-coordinates change to their opposite. This gives us:

  • A(1, 2) becomes A'(-1, 2)
  • B(3, 4) becomes B'(-3, 4)
  • C(5, 2) becomes C'(-5, 2)

So after flipping over the y-axis, our triangle is now at points A'(-1, 2), B'(-3, 4), and C'(-5, 2). This puts it in a different part of the graph.

Reflecting Over the Line y = x

What happens if we reflect over a line that isn’t one of the axes, like the line y = x? In this case, we swap the x and y positions for each point:

  • A(1, 2) becomes A'(2, 1)
  • B(3, 4) becomes B'(4, 3)
  • C(5, 2) becomes C'(2, 5)

Important Points to Remember

  1. For the x-axis: A(x, y) becomes A'(x, -y).
  2. For the y-axis: A(x, y) becomes A'(-x, y).
  3. For the line y = x: A(x, y) becomes A'(y, x).

In summary, with reflection, you’re flipping a shape over a line. The way the coordinates change gives you a new position that mirrors the original one. The more you practice this, the easier it will be, and before long, flipping shapes will feel natural!

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