If ‘A’ is the area of cross-section and ‘I’ is the moment of inertia of a given plane section, then radius of gyration (r) is given by the formula

A

$$ r = \frac{I}{A} $$

B

$$ r = \sqrt{\frac{I}{A}} $$

C

$$ r = \frac{A}{I} $$

D

$$ r = \sqrt{\frac{A}{I}} $$