radiation intensity

radiation intensity

Radiation from a point source varies as the inverse of the square of the distance. Complete the following table to predict the radiation intensity at each distance.

The distance in centimeters is 1, 2, 4, 6, 8, 10.
The radiation in cpm for the distance of 1 cm is 2000 cpm.
These are my predictions:
At a distance of 2 cm, the radiation is 500 cpm.
At the distance of 4 cm, the radiation is 125 cpm.
At the distance of 6 cm, the radiation is 55.6 cpm.
At the distance of 8 cm, the radiation is 31.25 cpm.
At the distance of 10 cm, the radiation is 20 cpm.
Is this correct? Or is it wrong if so how do I correct it?
Oh and at what distance would radiation cease completely?

Helppppp?! Please.