line Ac is a dilation of AB, with point B as center of dilation. Determine the scale factor.

coordinate A(-1,-1)
coordinate B(2,2)
coordinate C(5,5)

1 answer

To determine the scale factor of the dilation of line segment \( AB \) to line segment \( AC \) with point \( B \) as the center of dilation, we can use the formula for the scale factor, which is given by

\[ k = \frac{\text{distance from } B \text{ to } C}{\text{distance from } B \text{ to } A} \]

First, we need to calculate the distances from point \( B \) to points \( A \) and \( C \).

1. Calculate the distance from \( B \) to \( A \):

Coordinates:

  • \( A(-1, -1) \)
  • \( B(2, 2) \)

Using the distance formula, we have:

\[ d_{BA} = \sqrt{(x_B - x_A)^2 + (y_B - y_A)^2} \]

Substituting the coordinates:

\[ d_{BA} = \sqrt{(2 - (-1))^2 + (2 - (-1))^2} = \sqrt{(2 + 1)^2 + (2 + 1)^2} = \sqrt{3^2 + 3^2} = \sqrt{9 + 9} = \sqrt{18} = 3\sqrt{2} \]

2. Calculate the distance from \( B \) to \( C \):

Coordinates:

  • \( C(5, 5) \)

Again using the distance formula:

\[ d_{BC} = \sqrt{(x_B - x_C)^2 + (y_B - y_C)^2} \]

Substituting the coordinates:

\[ d_{BC} = \sqrt{(2 - 5)^2 + (2 - 5)^2} = \sqrt{(-3)^2 + (-3)^2} = \sqrt{9 + 9} = \sqrt{18} = 3\sqrt{2} \]

3. Calculate the scale factor \( k \):

Now substituting the distances into the scale factor formula:

\[ k = \frac{d_{BC}}{d_{BA}} = \frac{3\sqrt{2}}{3\sqrt{2}} = 1 \]

Thus, the scale factor of the dilation from \( AB \) to \( AC \) with \( B \) as the center of dilation is

\[ \boxed{1} \]