Ok, so the prefix giga means 1,000,000,000, and that times 39.3700787 (because 39.3700787 inches is a meter) is 39,370,078,700. so there are 39,370,078,700 inches in a gigameter. Hope this helps.

Something very big as 1 gigameter = 1,000,000,000 m (or a billion meters) = 1,000,000 km (or a million kilometers) the above is obvious... something which could be measured in gigameters could be the distance between planets for example

i am not shore i think that since we measure computer memory with kilobyte megabyte and so on that there also would be a megameter(mm?how will that work!) Gigameter(gm) tetrameter(tm) pentameter(pm) exameter(em or xm) and zettameter(zm)