Which of the following statements is true? (It may be one, more than one, or none of the following.) Select one or more:

a. The radius of gyration for a rectangle about its baseline is h/sqrt(3).
b. The radius of gyration of an area is the square root of I/A.
c. The radius of gyration of an area represents the place to put the force to change a distributed load into a point load.
d. The radius of gyration of an area is the same for both x and y.