L4 · Dilations and similarity

1. 1.

   Dilate point P(2, 3) about the origin by scale factor 4. Image?

   Answer. (8, 12)

   (x, y) → (4x, 4y) = (8, 12).

2. 2.

   Dilate point P(5, 3) about the origin by scale factor 3. Image?

   Answer. (15, 9)

   (x, y) → (3x, 3y) = (15, 9).

3. 3.

   Dilate point P(4, 3) about the origin by scale factor 4. Image?

   Answer. (16, 12)

   (x, y) → (4x, 4y) = (16, 12).

4. 4.

   Dilate point P(2, 3) about the origin by scale factor 3. Image?

   Answer. (6, 9)

   (x, y) → (3x, 3y) = (6, 9).

5. 5.

   Dilate point P(3, 4) about the origin by scale factor 2. Image? Write a complete answer — Malik will compare with a partner.

   Answer. (6, 8)

   (x, y) → (2x, 2y) = (6, 8).

6. 6.

   Dilate point P(2, 2) about the origin by scale factor 3. Image? Write a complete answer — Owen will compare with a partner.

   Answer. (6, 6)

   (x, y) → (3x, 3y) = (6, 6).

7. 7.

   Dilate point P(5, 4) about the origin by scale factor 4. Image? Write a complete answer — Luis will compare with a partner.

   Answer. (20, 16)

   (x, y) → (4x, 4y) = (20, 16).

8. 8.

   Dilate point P(4, 2) about the origin by scale factor 2. Image? Write a complete answer — Theo will compare with a partner.

   Answer. (8, 4)

   (x, y) → (2x, 2y) = (8, 4).

9. 9.

   Dilate point P(2, 4) about the origin by scale factor 3. Image? Write a complete answer — Nora will compare with a partner.

   Answer. (6, 12)

   (x, y) → (3x, 3y) = (6, 12).

10. 10.

    Dilate point P(3, 3) about the origin by scale factor 4. Image? Write a complete answer — Elena will compare with a partner.

    Answer. (12, 12)

    (x, y) → (4x, 4y) = (12, 12).

11. 11.

    Think

    Grace tried this problem:
    Dilate point P(4, 3) about the origin by scale factor 3. Image?
    Grace wrote (24, 9). That is not correct. What is the right answer?

    Answer. (12, 9)

    Grace’s answer (24, 9) is off. (x, y) → (3x, 3y) = (12, 9).

12. 12.

    Think

    Theo tried this problem:
    Dilate point P(2, 3) about the origin by scale factor 4. Image?
    Theo wrote (16, 12). That is not correct. What is the right answer?

    Answer. (8, 12)

    Theo’s answer (16, 12) is off. (x, y) → (4x, 4y) = (8, 12).

Original extra practice. Keys are computed from the items, not guessed.