Responder
**20. A stop sign is an octagon, an eight-sided polygon.**
**21.**
- **a.** The fraction of girls in the class is **4⁄9**.
- **b.** The ratio of boys to girls is **5 : 4**.
**22.**
Carla's mental division problem was **9 ÷ 3**, and the result is **3**.
Solución
Sure, let's address each of your questions one by one.
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### **20. A stop sign has the shape of an eight-sided polygon?**
**Answer:**
Yes, a stop sign typically has the shape of an **octagon**, which is an eight-sided polygon.
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### **21. There were 15 boys and 12 girls in the class.**
**a. What fraction of the class was made up of girls?**
**Solution:**
- **Total number of students** = Number of boys + Number of girls
= 15 boys + 12 girls
= **27 students**
- **Fraction of girls in the class** = Number of girls / Total number of students
= 12 / 27
= Simplify by dividing numerator and denominator by 3
= **4/9**
**Answer:**
The fraction of the class made up of girls is **4⁄9**.
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**b. What was the ratio of boys to girls in the class?**
**Solution:**
- **Number of boys** = 15
- **Number of girls** = 12
- **Ratio of boys to girls** = 15 : 12
= Simplify by dividing both numbers by 3
= **5 : 4**
**Answer:**
The ratio of boys to girls in the class is **5 : 4**.
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### **22. Verify Instead of dividing \( 4 \frac{1}{2} \) by \( 1 \frac{1}{2} \), Carla doubled before dividing mentally. What was Carla's mental division problem?**
**Understanding the Question:**
Carla was supposed to divide \( 4 \frac{1}{2} \) by \( 1 \frac{1}{2} \). Instead of performing this division directly, she **doubled** both the dividend and the divisor before dividing.
**Step-by-Step Solution:**
1. **Original Division Problem:**
\( 4 \frac{1}{2} \div 1 \frac{1}{2} \)
2. **Convert Mixed Numbers to Improper Fractions:**
- \( 4 \frac{1}{2} = \frac{9}{2} \)
- \( 1 \frac{1}{2} = \frac{3}{2} \)
3. **Carla's Approach:**
She **doubled** both the numerator and the denominator:
- New Dividend: \( \frac{9}{2} \times 2 = 9 \)
- New Divisor: \( \frac{3}{2} \times 2 = 3 \)
4. **Carla's Mental Division Problem:**
\( 9 \div 3 \)
5. **Solution to Carla's Problem:**
\( 9 \div 3 = 3 \)
**Verification through Original Division:**
- \( 4 \frac{1}{2} \div 1 \frac{1}{2} = \frac{9}{2} \div \frac{3}{2} = \frac{9}{2} \times \frac{2}{3} = \frac{9 \times 2}{2 \times 3} = \frac{18}{6} = 3 \)
**Answer:**
Carla's mental division problem was **9 ÷ 3**, and the result is **3**.
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