How can I calculate the gyration radius of one agglomerates?

Question

I have an agglomerate that contains 3 primary particles. All the particles have the same size. This is the coordination of each particle:

1: [-0.000215830119981885 0.00580096069141 0.000019986433775992] 2: [-0.000206949694807699 0.00582014973599176 0.000064949372544984] 3: [-0.000205902931506532 0.00580291909616662 -0.0000286588699038301]

and Rp=2.5e-5

I calculated the gyration radius myself and I achieved 2.12e-5 for the gyration radius! which is less than the primary particle radius. It is not possible!!

Could you please check it for me and tell me what is the problem? I checked it several time. Is it possible that an agglomerates contain 3 particles has gyration radius/Primary particle radius?

Regards, Fatemeh

I used the formula in the picture attached before:

Answer 1

I am new in this field, but I calculate Rg for your particles based on the following form of Rg eqn:

enter image description here

and got Rg = 3.94377e-05