Certainty and Knowledge

But something like the radius of the moon is knowledge because it was useful in mathematical calculations that we needed to do to land on the moon.

When I wrote about useless information here:

I wondered whether something like the radius of the moon was knowledge. The reason was that it’s a particular fact, like how many grains of sand there are on a beach, and not a general concept. I mostly associate knowledge with abstract concepts, but I don’t actually think that’s all it is.