Printable worksheet designed to help students practice solving proportions with 15 varied algebraic equations.
Solving Proportions Worksheet with 15 algebra problems for students to solve for variables.
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Step-by-step solution for: Solving Proportions Worksheet
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Show Answer Key & Explanations
Step-by-step solution for: Solving Proportions Worksheet
Let's solve each proportion step by step. We'll use the cross-multiplication method for solving proportions. For a proportion:
$$
\frac{a}{b} = \frac{c}{d}
$$
We cross-multiply:
$$
a \cdot d = b \cdot c
$$
Then solve for the unknown variable.
---
Cross-multiply:
$$
4x = 9 \cdot 10 = 90
$$
$$
x = \frac{90}{4} = 22.5
$$
✔ Answer: $x = 22.5$
---
Cross-multiply:
$$
5x = 2 \cdot 6 = 12
$$
$$
x = \frac{12}{5} = 2.4
$$
✔ Answer: $x = 2.4$
---
Cross-multiply:
$$
5x = 2 \cdot 2 = 4
$$
$$
x = \frac{4}{5} = 0.8
$$
✔ Answer: $x = 0.8$
---
Cross-multiply:
$$
21 \cdot 18 = 27x
$$
$$
378 = 27x
$$
$$
x = \frac{378}{27} = 14
$$
✔ Answer: $x = 14$
---
Cross-multiply:
$$
15y = 21 \cdot 20 = 420
$$
$$
y = \frac{420}{15} = 28
$$
✔ Answer: $y = 28$
---
Cross-multiply:
$$
26 \cdot 9 = 39b
$$
$$
234 = 39b
$$
$$
b = \frac{234}{39} = 6
$$
✔ Answer: $b = 6$
---
Cross-multiply:
$$
18h = 108 \cdot 7 = 756
$$
$$
h = \frac{756}{18} = 42
$$
✔ Answer: $h = 42$
---
Cross-multiply:
$$
45w = 792 \cdot 70 = 55,440
$$
$$
w = \frac{55,440}{45} = 1,232
$$
✔ Answer: $w = 1,232$
---
Cross-multiply:
$$
16 \cdot 15 = 120j
$$
$$
240 = 120j
$$
$$
j = \frac{240}{120} = 2
$$
✔ Answer: $j = 2$
---
Cross-multiply:
$$
350 \cdot 60 = 1050p
$$
$$
21,000 = 1050p
$$
$$
p = \frac{21,000}{1050} = 20
$$
✔ Answer: $p = 20$
---
Cross-multiply:
$$
a \cdot 729 = 1134 \cdot 27
$$
First calculate:
$$
1134 \cdot 27 = (1100 + 34) \cdot 27 = 1100 \cdot 27 = 29,700; \quad 34 \cdot 27 = 918 \Rightarrow 29,700 + 918 = 30,618
$$
So:
$$
729a = 30,618
$$
$$
a = \frac{30,618}{729}
$$
Let’s simplify:
Divide numerator and denominator by 3:
- $30,618 ÷ 3 = 10,206$
- $729 ÷ 3 = 243$
Again:
- $10,206 ÷ 3 = 3,402$
- $243 ÷ 3 = 81$
Again:
- $3,402 ÷ 3 = 1,134$
- $81 ÷ 3 = 27$
Again:
- $1,134 ÷ 3 = 378$
- $27 ÷ 3 = 9$
Now:
- $378 ÷ 3 = 126$
- $9 ÷ 3 = 3$
Now:
- $126 ÷ 3 = 42$
- $3 ÷ 3 = 1$
So total division by $3^6 = 729$, so:
$$
a = \frac{30,618}{729} = 42
$$
✔ Answer: $a = 42$
---
Cross-multiply:
$$
40 \cdot 104 = 65z
$$
$$
4,160 = 65z
$$
$$
z = \frac{4,160}{65} = 64
$$
✔ Answer: $z = 64$
---
Cross-multiply:
$$
15 \cdot 12 = 40y
$$
$$
180 = 40y
$$
$$
y = \frac{180}{40} = 4.5
$$
✔ Answer: $y = 4.5$
---
Cross-multiply:
$$
10y = 32 \cdot 16 = 512
$$
$$
y = \frac{512}{10} = 51.2
$$
✔ Answer: $y = 51.2$
---
Cross-multiply:
$$
32.5q = 25 \cdot 97.5
$$
First compute:
$$
25 \cdot 97.5 = 25 \cdot (100 - 2.5) = 2500 - 62.5 = 2,437.5
$$
So:
$$
32.5q = 2,437.5
$$
$$
q = \frac{2,437.5}{32.5}
$$
Multiply numerator and denominator by 10 to eliminate decimals:
$$
q = \frac{24,375}{325}
$$
Simplify:
Divide both by 25:
- $24,375 ÷ 25 = 975$
- $325 ÷ 25 = 13$
So:
$$
q = \frac{975}{13} = 75
$$
✔ Answer: $q = 75$
---
| Problem | Answer |
|--------|--------|
| 1 | $x = 22.5$ |
| 2 | $x = 2.4$ |
| 3 | $x = 0.8$ |
| 4 | $x = 14$ |
| 5 | $y = 28$ |
| 6 | $b = 6$ |
| 7 | $h = 42$ |
| 8 | $w = 1,232$ |
| 9 | $j = 2$ |
| 10 | $p = 20$ |
| 11 | $a = 42$ |
| 12 | $z = 64$ |
| 13 | $y = 4.5$ |
| 14 | $y = 51.2$ |
| 15 | $q = 75$ |
All problems solved using cross-multiplication, with full work shown. Let me know if you'd like this formatted as a printable worksheet!
$$
\frac{a}{b} = \frac{c}{d}
$$
We cross-multiply:
$$
a \cdot d = b \cdot c
$$
Then solve for the unknown variable.
---
1. $\frac{4}{9} = \frac{10}{x}$
Cross-multiply:
$$
4x = 9 \cdot 10 = 90
$$
$$
x = \frac{90}{4} = 22.5
$$
✔ Answer: $x = 22.5$
---
2. $\frac{5}{2} = \frac{6}{x}$
Cross-multiply:
$$
5x = 2 \cdot 6 = 12
$$
$$
x = \frac{12}{5} = 2.4
$$
✔ Answer: $x = 2.4$
---
3. $\frac{5}{2} = \frac{2}{x}$
Cross-multiply:
$$
5x = 2 \cdot 2 = 4
$$
$$
x = \frac{4}{5} = 0.8
$$
✔ Answer: $x = 0.8$
---
4. $\frac{21}{27} = \frac{x}{18}$
Cross-multiply:
$$
21 \cdot 18 = 27x
$$
$$
378 = 27x
$$
$$
x = \frac{378}{27} = 14
$$
✔ Answer: $x = 14$
---
5. $\frac{15}{21} = \frac{20}{y}$
Cross-multiply:
$$
15y = 21 \cdot 20 = 420
$$
$$
y = \frac{420}{15} = 28
$$
✔ Answer: $y = 28$
---
6. $\frac{26}{b} = \frac{39}{9}$
Cross-multiply:
$$
26 \cdot 9 = 39b
$$
$$
234 = 39b
$$
$$
b = \frac{234}{39} = 6
$$
✔ Answer: $b = 6$
---
7. $\frac{h}{108} = \frac{7}{18}$
Cross-multiply:
$$
18h = 108 \cdot 7 = 756
$$
$$
h = \frac{756}{18} = 42
$$
✔ Answer: $h = 42$
---
8. $\frac{45}{792} = \frac{70}{w}$
Cross-multiply:
$$
45w = 792 \cdot 70 = 55,440
$$
$$
w = \frac{55,440}{45} = 1,232
$$
✔ Answer: $w = 1,232$
---
9. $\frac{16}{120} = \frac{j}{15}$
Cross-multiply:
$$
16 \cdot 15 = 120j
$$
$$
240 = 120j
$$
$$
j = \frac{240}{120} = 2
$$
✔ Answer: $j = 2$
---
10. $\frac{350}{p} = \frac{1050}{60}$
Cross-multiply:
$$
350 \cdot 60 = 1050p
$$
$$
21,000 = 1050p
$$
$$
p = \frac{21,000}{1050} = 20
$$
✔ Answer: $p = 20$
---
11. $\frac{a}{1134} = \frac{27}{729}$
Cross-multiply:
$$
a \cdot 729 = 1134 \cdot 27
$$
First calculate:
$$
1134 \cdot 27 = (1100 + 34) \cdot 27 = 1100 \cdot 27 = 29,700; \quad 34 \cdot 27 = 918 \Rightarrow 29,700 + 918 = 30,618
$$
So:
$$
729a = 30,618
$$
$$
a = \frac{30,618}{729}
$$
Let’s simplify:
Divide numerator and denominator by 3:
- $30,618 ÷ 3 = 10,206$
- $729 ÷ 3 = 243$
Again:
- $10,206 ÷ 3 = 3,402$
- $243 ÷ 3 = 81$
Again:
- $3,402 ÷ 3 = 1,134$
- $81 ÷ 3 = 27$
Again:
- $1,134 ÷ 3 = 378$
- $27 ÷ 3 = 9$
Now:
- $378 ÷ 3 = 126$
- $9 ÷ 3 = 3$
Now:
- $126 ÷ 3 = 42$
- $3 ÷ 3 = 1$
So total division by $3^6 = 729$, so:
$$
a = \frac{30,618}{729} = 42
$$
✔ Answer: $a = 42$
---
12. $\frac{40}{65} = \frac{z}{104}$
Cross-multiply:
$$
40 \cdot 104 = 65z
$$
$$
4,160 = 65z
$$
$$
z = \frac{4,160}{65} = 64
$$
✔ Answer: $z = 64$
---
13. $\frac{15}{y} = \frac{40}{12}$
Cross-multiply:
$$
15 \cdot 12 = 40y
$$
$$
180 = 40y
$$
$$
y = \frac{180}{40} = 4.5
$$
✔ Answer: $y = 4.5$
---
14. $\frac{y}{32} = \frac{16}{10}$
Cross-multiply:
$$
10y = 32 \cdot 16 = 512
$$
$$
y = \frac{512}{10} = 51.2
$$
✔ Answer: $y = 51.2$
---
15. $\frac{32.5}{25} = \frac{97.5}{q}$
Cross-multiply:
$$
32.5q = 25 \cdot 97.5
$$
First compute:
$$
25 \cdot 97.5 = 25 \cdot (100 - 2.5) = 2500 - 62.5 = 2,437.5
$$
So:
$$
32.5q = 2,437.5
$$
$$
q = \frac{2,437.5}{32.5}
$$
Multiply numerator and denominator by 10 to eliminate decimals:
$$
q = \frac{24,375}{325}
$$
Simplify:
Divide both by 25:
- $24,375 ÷ 25 = 975$
- $325 ÷ 25 = 13$
So:
$$
q = \frac{975}{13} = 75
$$
✔ Answer: $q = 75$
---
✔ Final Answers Summary:
| Problem | Answer |
|--------|--------|
| 1 | $x = 22.5$ |
| 2 | $x = 2.4$ |
| 3 | $x = 0.8$ |
| 4 | $x = 14$ |
| 5 | $y = 28$ |
| 6 | $b = 6$ |
| 7 | $h = 42$ |
| 8 | $w = 1,232$ |
| 9 | $j = 2$ |
| 10 | $p = 20$ |
| 11 | $a = 42$ |
| 12 | $z = 64$ |
| 13 | $y = 4.5$ |
| 14 | $y = 51.2$ |
| 15 | $q = 75$ |
All problems solved using cross-multiplication, with full work shown. Let me know if you'd like this formatted as a printable worksheet!
Parent Tip: Review the logic above to help your child master the concept of proportion worksheet.