Let's simplify each of the square roots step by step. We'll look for perfect square factors of each number under the square root and then simplify.
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1. √18
Break 18 into factors:
- 18 = 9 × 2
- 9 is a perfect square: √9 = 3
So:
$$
\sqrt{18} = \sqrt{9 \times 2} = \sqrt{9} \cdot \sqrt{2} = 3\sqrt{2}
$$
✔ Answer: $ 3\sqrt{2} $
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2. √27
Break 27 into factors:
- 27 = 9 × 3
- 9 is a perfect square: √9 = 3
So:
$$
\sqrt{27} = \sqrt{9 \times 3} = \sqrt{9} \cdot \sqrt{3} = 3\sqrt{3}
$$
✔ Answer: $ 3\sqrt{3} $
---
3. √8
Break 8 into factors:
- 8 = 4 × 2
- 4 is a perfect square: √4 = 2
So:
$$
\sqrt{8} = \sqrt{4 \times 2} = \sqrt{4} \cdot \sqrt{2} = 2\sqrt{2}
$$
✔ Answer: $ 2\sqrt{2} $
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4. √5
5 is a prime number and has no perfect square factors other than 1.
So:
$$
\sqrt{5} \text{ cannot be simplified further.}
$$
✔ Answer: $ \sqrt{5} $
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5. √28
Break 28 into factors:
- 28 = 4 × 7
- 4 is a perfect square: √4 = 2
So:
$$
\sqrt{28} = \sqrt{4 \times 7} = \sqrt{4} \cdot \sqrt{7} = 2\sqrt{7}
$$
✔ Answer: $ 2\sqrt{7} $
---
6. √75
Break 75 into factors:
- 75 = 25 × 3
- 25 is a perfect square: √25 = 5
So:
$$
\sqrt{75} = \sqrt{25 \times 3} = \sqrt{25} \cdot \sqrt{3} = 5\sqrt{3}
$$
✔ Answer: $ 5\sqrt{3} $
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7. √45
Break 45 into factors:
- 45 = 9 × 5
- 9 is a perfect square: √9 = 3
So:
$$
\sqrt{45} = \sqrt{9 \times 5} = \sqrt{9} \cdot \sqrt{5} = 3\sqrt{5}
$$
✔ Answer: $ 3\sqrt{5} $
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8. √32
Break 32 into factors:
- 32 = 16 × 2
- 16 is a perfect square: √16 = 4
So:
$$
\sqrt{32} = \sqrt{16 \times 2} = \sqrt{16} \cdot \sqrt{2} = 4\sqrt{2}
$$
✔ Answer: $ 4\sqrt{2} $
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9. √36
36 is a perfect square:
- √36 = 6
✔ Answer: $ 6 $
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10. √128
Break 128 into factors:
- 128 = 64 × 2
- 64 is a perfect square: √64 = 8
So:
$$
\sqrt{128} = \sqrt{64 \times 2} = \sqrt{64} \cdot \sqrt{2} = 8\sqrt{2}
$$
✔ Answer: $ 8\sqrt{2} $
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✔ Final Answers:
| Problem | Simplified Form |
|--------|------------------|
| 1. √18 | $ 3\sqrt{2} $ |
| 2. √27 | $ 3\sqrt{3} $ |
| 3. √8 | $ 2\sqrt{2} $ |
| 4. √5 | $ \sqrt{5} $ |
| 5. √28 | $ 2\sqrt{7} $ |
| 6. √75 | $ 5\sqrt{3} $ |
| 7. √45 | $ 3\sqrt{5} $ |
| 8. √32 | $ 4\sqrt{2} $ |
| 9. √36 | $ 6 $ |
| 10. √128 | $ 8\sqrt{2} $ |
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Key Strategy: Always look for the largest perfect square that divides the number under the square root, then use the property:
$$
\sqrt{a \times b} = \sqrt{a} \cdot \sqrt{b}
$$
and simplify accordingly.
Parent Tip: Review the logic above to help your child master the concept of simplifying square roots worksheet.