Ratios Introduction — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Multiply both parts of 1:2 by 3 to get the equivalent ratio 3:6.
Multiplying both parts by the same number keeps the ratio equivalent: 1:2 becomes 3:6.
2. An equivalent ratio of 2:5 with first part 6 is 6:15.
Multiplying 2 by 3 gives 6, and 5 by 3 gives 15, so 2:5 = 6:15.
3. Simplify 4:6 by dividing both parts by 2 to get 2:3.
Dividing both 4 and 6 by 2 gives 2:3, the simplest form of 4:6.
4. The ratio 10:15 in simplest form is 2:3.
The greatest common factor of 10 and 15 is 5, and 10:15 divided by 5 is 2:3.
5. If a recipe uses 2 cups flour to 1 cup sugar, then 4 cups flour needs 2 cups sugar.
Doubling both parts keeps 2:1 equivalent to 4:2, so 4 cups flour pairs with 2 cups sugar.
6. Multiply 3:4 by 5 to find the equivalent ratio 15:20.
3 times 5 is 15 and 4 times 5 is 20, so 3:4 = 15:20.
7. Simplify the ratio 12:8 to lowest terms: 3:2.
12 and 8 share factor 4; dividing gives 3:2, the simplest form.
8. An equivalent ratio of 5:7 with first part 25 is 25:35.
Multiplying both parts of 5:7 by 5 gives 25:35, an equivalent ratio.
9. If 1:3 is a ratio, doubling both parts gives 2:6.
Doubling each part of 1:3 produces 2:6, which is equivalent.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
1:2 multiplied by 4
→ 4:8
4:8
10:15 simplified
→ 2:3
2:3
3:5 multiplied by 2
→ 6:10
6:10
8:12 simplified
→ 2:3 (from 8:12 divided by 4)
2:3 (from 8:12 divided by 4)
Each match shows an equivalent ratio formed by scaling both parts by the same factor.