L13 · Equivalent ratios

1. 1.

   Complete the equivalent ratio: 4 : 4 = 12 : ?

   A	B
   4	4
   12	?

   Answer. 12

   Multiply both parts by 3: 4 × 3 = 12.

2. 2.

   Complete the equivalent ratio: 4 : 5 = 8 : ?

   A	B
   4	5
   8	?

   Answer. 10

   Multiply both parts by 2: 5 × 2 = 10.

3. 3.

   Are the ratios 5 : 5 and 25 : 25 equivalent?

   Answer. yes

   Both simplify to 1 : 1, so they are equivalent.

4. 4.

   Are the ratios 5 : 4 and 25 : 20 equivalent?

   Answer. yes

   Both simplify to 5 : 4, so they are equivalent.

5. 5.

   Complete the equivalent ratio: 5 : 9 = 20 : ? Then Owen needs 5 of that amount. What is the total they need?

   A	B
   5	9
   20	?

   Answer. 180

   Multiply both parts by 4: 9 × 4 = 36. Then multiply by 5: 180.

6. 6.

   Complete the equivalent ratio: 7 : 8 = 28 : ? Then Mei needs 3 of that amount. What is the total they need?

   A	B
   7	8
   28	?

   Answer. 96

   Multiply both parts by 4: 8 × 4 = 32. Then multiply by 3: 96.

7. 7.

   Are the ratios 6 : 7 and 18 : 21 equivalent? Write a complete answer — Elena will compare with a partner.

   Answer. yes

   Both simplify to 6 : 7, so they are equivalent.

8. 8.

   Are the ratios 3 : 5 and 9 : 15 equivalent? Write a complete answer — Ava will compare with a partner.

   Answer. yes

   Both simplify to 3 : 5, so they are equivalent.

9. 9.

   Complete the equivalent ratio: 6 : 6 = 12 : ? Then Ava needs 4 of that amount. What is the total they need?

   A	B
   6	6
   12	?

   Answer. 48

   Multiply both parts by 2: 6 × 2 = 12. Then multiply by 4: 48.

10. 10.

    Are the ratios 6 : 3 and 30 : 15 equivalent? Write a complete answer — Ava will compare with a partner.

    Answer. yes

    Both simplify to 2 : 1, so they are equivalent.

11. 11.

    Think

    Priya tried this problem:
    Are the ratios 4 : 4 and 20 : 20 equivalent?
    Priya wrote no. That is not correct. What is the right answer?

    Answer. yes

    Priya’s answer no is off. Both simplify to 1 : 1, so they are equivalent.

12. 12.

    Think

    Nora tried this problem:
    Complete the equivalent ratio: 6 : 9 = 30 : ?
    Nora wrote -45. That is not correct. What is the right answer?

    A	B
    6	9
    30	?

    Answer. 45

    Nora’s answer -45 is off. Multiply both parts by 5: 9 × 5 = 45.

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