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Cogito

Grade 8 Math · Chapter 2 · Lesson 1

Practice Worksheet

Dilations

The move that does change size.

10 problems · about 18 minutes · 8.G.A.3

NameDate

Figure — use these to answer the problems

Change the scale factor and compare with the dashed original.
Scale factor2
Figure 1

Warm-Up Review

From earlier lessons. Loosen up before the new work.

2 problems

  1. From “Sequences of Moves”

    Rotated 90° three times. Total turn in degrees?

    Answer

  2. From “What a Transformation Does to Coordinates”

    (6, −2) translated 3 left. What is the new x?

    Answer

Warm Up

Straightforward practice. Get the method working first.

4 problems

  1. A side of 9 dilated by 3. New length?

    Answer

  2. What does a dilation leave unchanged?

    • The angles.
    • The lengths.

  3. A side of 5 dilated by 4. New length?

    Answer

  4. A side of 12 dilated by 1/2. New length?

    Answer

Build It Up

The same ideas with more to keep track of.

2 problems

  1. An angle of 75 dilated by 2. What is it now?

    Answer

  2. Is a dilation a rigid motion?

    • No. Lengths change.
    • Yes.

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

2 problems

  1. The Enlargement

    A side of 7 is dilated by 3. How long is it now?

    Answer

  2. The Angle

    An angle of 40 degrees is dilated by 5. What is it now?

    Answerdegrees