Math Problem Statement

Write the coordinates of the vertices after a reflection over the line y=1.

Write the coordinates of the vertices after a reflection over the line y=1.

Solution

To find the coordinates of the vertices BB, CC, DD, and EE after a reflection over the line y=1y = 1, we need to follow these steps:

  1. Identify the coordinates of each vertex.

    • B=(8,8)B = (-8, -8)
    • C=(7,2)C = (-7, -2)
    • D=(4,3)D = (-4, 3)
    • E=(5,3)E = (-5, -3)
  2. Reflect each point across the line y=1y = 1.

    • When reflecting a point (x,y)(x, y) over a horizontal line y=ky = k, the reflected point will be (x,2ky)(x, 2k - y).

Since y=1y = 1, we can apply this formula to each vertex.

Calculations

  • Point B=(8,8)B = (-8, -8): y=2(1)(8)=2+8=10y' = 2(1) - (-8) = 2 + 8 = 10 Reflected point of BB: (8,10)(-8, 10).

  • Point C=(7,2)C = (-7, -2): y=2(1)(2)=2+2=4y' = 2(1) - (-2) = 2 + 2 = 4 Reflected point of CC: (7,4)(-7, 4).

  • Point D=(4,3)D = (-4, 3): y=2(1)3=23=1y' = 2(1) - 3 = 2 - 3 = -1 Reflected point of DD: (4,1)(-4, -1).

  • Point E=(5,3)E = (-5, -3): y=2(1)(3)=2+3=5y' = 2(1) - (-3) = 2 + 3 = 5 Reflected point of EE: (5,5)(-5, 5).

Reflected Coordinates

After reflecting over the line y=1y = 1, the coordinates of the vertices are:

  • B=(8,10)B' = (-8, 10)
  • C=(7,4)C' = (-7, 4)
  • D=(4,1)D' = (-4, -1)
  • E=(5,5)E' = (-5, 5)

Would you like further details on how reflections work, or have any specific questions?


Here are some follow-up questions:

  1. How would the coordinates change if the reflection line was y=1y = -1 instead of y=1y = 1?
  2. What would be the new coordinates if the shape was rotated 90 degrees around the origin?
  3. How can we generalize the reflection formula for any line y=ky = k?
  4. What if we wanted to reflect over a vertical line, say x=4x = -4?
  5. How would you determine the distance between the original points and their reflected images?

Tip: For any point reflection, the distance between the original and the reflected point is always twice the distance from the original point to the line of reflection.

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Math Problem Analysis

Mathematical Concepts

Geometry
Reflections
Coordinate Geometry

Formulas

Reflection formula: (x, 2k - y) for reflection over y = k

Theorems

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Suitable Grade Level

Grades 8-10