This image displays the answer key for the 'Common Square Roots (A)' worksheet, providing the correct solutions for calculating the principal square roots of various perfect squares.

The image you've uploaded is a completed worksheet titled "Common Square Roots (A) Answers" from Math-Drills.com, which contains the principal (positive) square roots of various perfect squares. The task was to calculate the positive square root of each number, and all answers have already been filled in correctly.

Let me walk through how these solutions are derived and confirm their accuracy.

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🔍 Understanding the Task

We are asked to find the principal (positive) square root of each number. That means for any number $ x $, we want the positive value $ y $ such that:
$$
y^2 = x
$$

For example:
- $ \sqrt{144} = 12 $ because $ 12 \times 12 = 144 $

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✔ Verification of Each Answer

Here's a quick verification of each answer:

| Expression | Answer | Verification |
|-----------|--------|--------------|
| $ \sqrt{144} $ | 12 | $ 12^2 = 144 $ ✔ |
| $ \sqrt{100} $ | 10 | $ 10^2 = 100 $ ✔ |
| $ \sqrt{25} $ | 5 | $ 5^2 = 25 $ ✔ |
| $ \sqrt{9} $ | 3 | $ 3^2 = 9 $ ✔ |
| $ \sqrt{4} $ | 2 | $ 2^2 = 4 $ ✔ |
| $ \sqrt{900} $ | 30 | $ 30^2 = 900 $ ✔ |
| $ \sqrt{121} $ | 11 | $ 11^2 = 121 $ ✔ |
| $ \sqrt{225} $ | 15 | $ 15^2 = 225 $ ✔ |
| $ \sqrt{64} $ | 8 | $ 8^2 = 64 $ ✔ |
| $ \sqrt{169} $ | 13 | $ 13^2 = 169 $ ✔ |
| $ \sqrt{81} $ | 9 | $ 9^2 = 81 $ ✔ |
| $ \sqrt{6400} $ | 80 | $ 80^2 = 6400 $ ✔ |
| $ \sqrt{625} $ | 25 | $ 25^2 = 625 $ ✔ |
| $ \sqrt{4900} $ | 70 | $ 70^2 = 4900 $ ✔ |
| $ \sqrt{1} $ | 1 | $ 1^2 = 1 $ ✔ |
| $ \sqrt{196} $ | 14 | $ 14^2 = 196 $ ✔ |
| $ \sqrt{3600} $ | 60 | $ 60^2 = 3600 $ ✔ |
| $ \sqrt{16} $ | 4 | $ 4^2 = 16 $ ✔ |
| $ \sqrt{49} $ | 7 | $ 7^2 = 49 $ ✔ |
| $ \sqrt{400} $ | 20 | $ 20^2 = 400 $ ✔ |
| $ \sqrt{1600} $ | 40 | $ 40^2 = 1600 $ ✔ |
| $ \sqrt{2500} $ | 50 | $ 50^2 = 2500 $ ✔ |
| $ \sqrt{8100} $ | 90 | $ 90^2 = 8100 $ ✔ |
| $ \sqrt{36} $ | 6 | $ 6^2 = 36 $ ✔ |

✔ All answers are correct.

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📌 Summary

- This worksheet tests knowledge of perfect squares.
- All answers provided are accurate.
- The principal (positive) square root is always taken, so negative roots are not considered.
- There are 24 problems, and all are correctly solved.

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✔ Final Score: 24 / 24

If this were a graded assignment, the student would receive full credit.

Let me know if you'd like a version of this worksheet without answers (for practice), or if you want help with non-perfect square roots!