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Dilate (6, -4) by scale factor 1/2

Step by step, with the reason for every step · Dilations about the origin · Geometry

Step by step

The question

Question: dilate the point P(6, −4) by scale factor ½.

P = (6, −4)
= scale factor 12

1 Draw the shape

Put the point on the grid.

2 Multiply each point

Scale factor one half makes the shape half as big.

Every number is multiplied by one half.

scale factor ½ → half as big

We call the new point P prime.

The little mark means: the new P.

P is (6, −4).

Half of 6 is 3.

Half of −4 is −2.

So P' is (3, −2).

P(6, −4) → (12 × 6, 12 × −4) = P'(3, −2)

Careful!

Half as big means divide every number by 2.

Taking 2 away would slide the shape.

Careful: not P'(6 − 2, −4 − 2) ✗

3 The new point

So the image is P'(3, −2).

P' = (3, −2)

4 Check

Let's check P.

Draw a line from O through P' to P.

From O to P: right 6, down 4.

O → P: right 6, down 4

From O to P': right 3, down 2.

That is half the moves to P.

So P' is on the same line from O, half as far.

Right!

O → P': right 3, down 2

Let's look back.

First: draw the shape.

Then: multiply each point.

Then: the new point.

Last: check.

Answer
P' = (3, −2)

Your turn

Try this one yourself, then check:

P(6, −6): scale factor 12
Show the answer
P' = (3, −3)

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