Question

If a figure is dilated by a scale factor of 3, what were the coordinates of the pre-image of W'(-6, 9)?

W(-18, 27)
W(-3, 12)
W(-2,3)
W(-9, 6)

Answer 1

W(- 2, 3 )

Explanation:

Assuming the dilatation is centred at the origin, then

the coordinates of W' are 3 times the original coordinates.

Thus to find the pre- image divide the image coordinates by 3

W(- 6, 9 ) → W(- 6 ÷ 3, 9 ÷ 3 ) → W(- 2, 3 )

Answer 2

A) W(-2, 3)

Explanation:

A dilation is a geometric transformation that increases or decreases the original size of a shape by a scale factor. In this instance, the scale factor is three, and the coordinates of the image is W'(-6, 9). So, we need to calculate the coordinates of the original pre-image.

Basically, when we have the scale factor of a pre-image, we simply multiply it by it's original coordinates.

(-6)/3 = (-2)

9/3 = 3

W(-2, 3) would be our original coordinates prior to the scale factor of 3.