Question

A pre-image and its image have coordinates (-3,-6) and (-1, -2), respectively. Which of the following options representsthe scale factor used in the dilation?321/21/3

Answer 1

ANSWER

1/3

EXPLANATION

The pre-image has coordinates (-3, -6) and the image has coordinates (-1, -2)

The scale factor is the number by which the pre-image was increased or decreased in size through dilation.

To find that, we pick either of the x or y coordinates of the pre-image and image and then we have:

$\text{scale factor =}\frac{coordinate\text{ of image}}{coordinate\text{ of preimage}}$

Let us pick the x coordinates.

We have that the scale factor is:

$SF\text{ = }\frac{-1}{-3}\text{ = }\frac{1}{3}$

The scale factor is 1/3.