Let's solve each problem using the
percent proportion method:
$$
\frac{\text{is (part)}}{\text{of (whole)}} = \frac{\%}{100}
$$
We'll use cross-multiplication:
Multiply diagonally and then divide by the remaining number.
---
1) What is 25% of 64?
Set up:
$$
\frac{x}{64} = \frac{25}{100}
$$
Cross-multiply:
$$
x \cdot 100 = 25 \cdot 64 \\
100x = 1600 \\
x = \frac{1600}{100} = 16
$$
✔ Answer = 16
---
2) 54 is 90% of what number?
Set up:
$$
\frac{54}{x} = \frac{90}{100}
$$
Cross-multiply:
$$
54 \cdot 100 = 90 \cdot x \\
5400 = 90x \\
x = \frac{5400}{90} = 60
$$
✔ Answer = 60
---
3) 12 is what percent of 80?
Set up:
$$
\frac{12}{80} = \frac{x}{100}
$$
Cross-multiply:
$$
12 \cdot 100 = 80 \cdot x \\
1200 = 80x \\
x = \frac{1200}{80} = 15
$$
✔ Answer = 15%
---
4) What is 30% of 90?
Set up:
$$
\frac{x}{90} = \frac{30}{100}
$$
Cross-multiply:
$$
x \cdot 100 = 30 \cdot 90 \\
100x = 2700 \\
x = \frac{2700}{100} = 27
$$
✔ Answer = 27
---
5) 8 is 40% of what number?
Set up:
$$
\frac{8}{x} = \frac{40}{100}
$$
Cross-multiply:
$$
8 \cdot 100 = 40 \cdot x \\
800 = 40x \\
x = \frac{800}{40} = 20
$$
✔ Answer = 20
---
6) 24 is what percent of 60?
Set up:
$$
\frac{24}{60} = \frac{x}{100}
$$
Cross-multiply:
$$
24 \cdot 100 = 60 \cdot x \\
2400 = 60x \\
x = \frac{2400}{60} = 40
$$
✔ Answer = 40%
---
7) 6 is 20% of what number?
Set up:
$$
\frac{6}{x} = \frac{20}{100}
$$
Cross-multiply:
$$
6 \cdot 100 = 20 \cdot x \\
600 = 20x \\
x = \frac{600}{20} = 30
$$
✔ Answer = 30
---
8) What is 60% of 60?
Set up:
$$
\frac{x}{60} = \frac{60}{100}
$$
Cross-multiply:
$$
x \cdot 100 = 60 \cdot 60 \\
100x = 3600 \\
x = \frac{3600}{100} = 36
$$
✔ Answer = 36
---
9) 18 is what percent of 24?
Set up:
$$
\frac{18}{24} = \frac{x}{100}
$$
Cross-multiply:
$$
18 \cdot 100 = 24 \cdot x \\
1800 = 24x \\
x = \frac{1800}{24} = 75
$$
✔ Answer = 75%
---
10) 22 is 40% of what number?
Set up:
$$
\frac{22}{x} = \frac{40}{100}
$$
Cross-multiply:
$$
22 \cdot 100 = 40 \cdot x \\
2200 = 40x \\
x = \frac{2200}{40} = 55
$$
✔ Answer = 55
---
✔ Final Answers:
| Problem | Equation | Answer |
|--------|---------|--------|
| 1 | $\frac{x}{64} = \frac{25}{100}$ |
16 |
| 2 | $\frac{54}{x} = \frac{90}{100}$ |
60 |
| 3 | $\frac{12}{80} = \frac{x}{100}$ |
15% |
| 4 | $\frac{x}{90} = \frac{30}{100}$ |
27 |
| 5 | $\frac{8}{x} = \frac{40}{100}$ |
20 |
| 6 | $\frac{24}{60} = \frac{x}{100}$ |
40% |
| 7 | $\frac{6}{x} = \frac{20}{100}$ |
30 |
| 8 | $\frac{x}{60} = \frac{60}{100}$ |
36 |
| 9 | $\frac{18}{24} = \frac{x}{100}$ |
75% |
|10 | $\frac{22}{x} = \frac{40}{100}$ |
55 |
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Parent Tip: Review the logic above to help your child master the concept of percent proportion worksheet answers.
