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Dilate (2, 3) by scale factor 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(2, 3) by scale factor 2.

P = (2, 3)
= scale factor 2

1 Draw the shape

Put the point on the grid.

2 Multiply each point

Scale factor 2 makes the shape 2 times as big.

Every number is multiplied by 2.

scale factor 2 → 2 times as big

We call the new point P prime.

The little mark means: the new P.

P is (2, 3).

2 times 2 is 4.

2 times 3 is 6.

So P' is (4, 6).

P(2, 3) → (2 × 2, 2 × 3) = P'(4, 6)

Careful!

A dilation multiplies.

Adding 2 would slide the shape, not make it bigger.

Careful: not P'(2 + 2, 3 + 2) ✗

3 The new point

So the image is P'(4, 6).

P' = (4, 6)

4 Check

Let's check P.

Draw a line from O through P to P'.

From O to P: right 2, up 3.

O → P: right 2, up 3

From O to P': right 4, up 6.

That is 2 times the moves to P.

So P' is on the same line from O, 2 times as far.

Right!

O → P': right 4, up 6

Let's look back.

First: draw the shape.

Then: multiply each point.

Then: the new point.

Last: check.

Answer
P' = (4, 6)

Your turn

Try this one yourself, then check:

P(1, 3): scale factor 2
Show the answer
P' = (2, 6)

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