Triangle ABC was translated according to the rule (x, y) → (x + 1.5, y – 3.5) to create the image ΔA'B'C' shown on the coordinate plane.

Which graph shows the pre-image, ΔABC?

On a coordinate plane, a triangle has points A prime (negative 1, 2), B prime (1, negative 1), C prime (negative 5, negative 1).
On a coordinate plane, a triangle has points A (0.5, negative 1.5), B (0.5, negative 4.5), C (negative 3.5, negative 4.5).
On a coordinate plane, a triangle has points A (2.5, 0.5), B (2.5, 2.5), C (negative 1.5, negative 2.5).
On a coordinate plane, a triangle has points A (negative 4.5, 3.5), B (negative 4.5, 0.5), C (negative 8.5, 0.5).
On a coordinate plane, a triangle has points A (negative 2.5, 5.5), B (negative 2.5, 2.5), C (negative 6.5, 2.5).

1 answer

To find the pre-image triangle \( \Delta ABC \) from the image triangle \( \Delta A'B'C' \), we need to reverse the translation given by the rule \( (x, y) \rightarrow (x + 1.5, y - 3.5) \).

To find the original coordinates, we apply the inverse of the translation: \[ (x', y') \rightarrow (x' - 1.5, y' + 3.5) \]

Now, let's find the original coordinates of points \( A', B', \) and \( C' \):

  • The coordinates of \( A' \) are \((-1, 2)\):

    • \( x_A = -1 - 1.5 = -2.5 \)
    • \( y_A = 2 + 3.5 = 5.5 \)
    • So \( A(-2.5, 5.5) \).
  • The coordinates of \( B' \) are \((1, -1)\):

    • \( x_B = 1 - 1.5 = -0.5 \)
    • \( y_B = -1 + 3.5 = 2.5 \)
    • So \( B(-0.5, 2.5) \).
  • The coordinates of \( C' \) are \((-5, -1)\):

    • \( x_C = -5 - 1.5 = -6.5 \)
    • \( y_C = -1 + 3.5 = 2.5 \)
    • So \( C(-6.5, 2.5) \).

These calculations provide us with the pre-image points \( A(-2.5, 5.5) \), \( B(-0.5, 2.5) \), and \( C(-6.5, 2.5) \).

Now we can see which graph shows the pre-image triangle \( \Delta ABC \):

  • The closest coordinates from the options given that match what we calculated is:
    • \( A(-2.5, 5.5) \)
    • \( B(-2.5, 2.5) \)
    • \( C(-6.5, 2.5) \)

Based on these calculations, the correct triangle is: On a coordinate plane, a triangle has points A (negative 2.5, 5.5), B (negative 2.5, 2.5), C (negative 6.5, 2.5).