1. **State the problem:**
We have a rectangle with an original length of 8 cm and an area of 20 cm². We want to find the original width, then analyze what happens when the length is increased by 2 cm and the area increases by 4 cm². Finally, we check if the width decreases by less than 5% as Noah claims.
2. **Find the original width:**
The area of a rectangle is given by $$\text{Area} = \text{Length} \times \text{Width}$$
Given the original area is 20 cm² and length is 8 cm, we solve for width:
$$\text{Width} = \frac{\text{Area}}{\text{Length}} = \frac{20}{8} = 2.5 \text{ cm}$$
3. **Find the new length and new area:**
The length is increased by 2 cm:
$$\text{New Length} = 8 + 2 = 10 \text{ cm}$$
The area is increased by 4 cm²:
$$\text{New Area} = 20 + 4 = 24 \text{ cm}^2$$
4. **Find the new width:**
Using the new area and new length:
$$\text{New Width} = \frac{\text{New Area}}{\text{New Length}} = \frac{24}{10} = 2.4 \text{ cm}$$
5. **Calculate the percentage decrease in width:**
The width decreased from 2.5 cm to 2.4 cm, so the decrease is:
$$\text{Decrease} = 2.5 - 2.4 = 0.1 \text{ cm}$$
Percentage decrease is:
$$\frac{0.1}{2.5} \times 100 = 4\%$$
6. **Conclusion:**
Since the width decreases by 4%, which is less than 5%, Noah is correct.
**Final answer:** Noah's statement that the width decreases by less than 5% is correct.
Rectangle Width Change
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