Radius of gyration of four equal masses at the corners of a square

The same question, asked 2 times: 19 Apr 2025 S1, 25 Apr 2025 S1. Every wording below, oldest first.

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Question 1
19 Apr 2025 S1
20 $Four particles each of mass M are placed at the corners of a square of side L . The radius of gyration of the system about an axis perpendicular to the square and passing through its center is$
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Question 2
25 Apr 2025 S1
12 $Four particles each of mass M are placed at the corners of a square of side L . The radius of gyration of the system about an axis perpendicular to the square and passing through its center is$
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Question 1