 So, this one says, when molybdenum crystallizes, it forms body-centered cubic cells. The unit cell edge length is 314.1 picometers. What is the radius and picometers of a polonium atom? So, body-centered cubic cell, unit cell edge, 314.1. And then the body cell, the body-centered, that's the long, right, so it's going to be square root of 3. So, we're looking for the radius of molybdenum, so just plug and chug, 314.1 picometers times the square root of 5.4, do so for the hypothesis that we couldn't get after. Any questions on this one? Again, if you can't remember how to do it geometrically, just memorize the form, it's probably the easiest way to do it. Questions, questions? What was that? This was the body-centered. It's not on the list, okay? Yeah, that's what I was saying, I was going to make up a new one. That's the question you were asking, right? Yeah, okay, cool. Yeah, it's not on the, it just came out of my head, you know, so. Okay, any other questions on that one? Yeah, cool.