Interesting information:
The ballistic missile intercept range of a dual-function anti-aircraft system is largely smaller than the intercept radius of atmospheric threats. In general they are 5 times smaller.
In the case of the FD-2000B if it has a range of 250 km against aircraft as mentioned in the text it would be able to intercept ballistic missiles at about 50 km. If the range against aircraft is 125 km as in the graph this distance would be about 25 km.
Of course, these are general estimates and have to do with the physics of intercept and radar detection.
Another interesting fact about endoatmospheric antiballistic missiles is that the intercept radius decreases as the speed of the ballistic “missile” (or the reentry vehicle) increases.
For example, if a given system is capable of intercepting a re-entry vehicle that dives at 2 km/s relative to a short-range missile, within a radius of 50 km, a re-entry vehicle at 3 km/s relative to a missile medium range, would be intercepted at 30 km, one at 4 km/s at 15 km, etc. *I do not pretend to be exact in the numbers, being just illustrative)
An interesting data from the unmissable graph makes it clear that a low-flying subsonic cruise missile that flies close to the ground is more difficult to intercept (15 km intercept radius) than a high-flying supersonic cruise missile (50 km of intercept radius).