The phrase "kilometer radius" refers to a distance that extends for one kilometer in every direction from a specific point. It represents a circle with a diameter of two kilometers. Full definition
Stay away from areas within a 6-5/5 kilometer radius of the volcano,» he said on his Twitter account. (thejakartapost.com)
Oxnead Guesthouse is also within 10 kilometers radius from well known golf courses like Woodhill, Wingate Park, Silver Lakes, Irene and Pretoria Country Club. (travelground.com)
On 21 August, the European Union announced a series of measures to contain it, including an export ban on ruminants — as well as their semen, ova, and embryos — in a 150 - kilometer radius around stricken areas. (sciencemag.org)