A dairy farmer uses a storage silo that is in a shape of a right circular cylinder above. If the volume of the silo is 72 pi cubic yards, what is the diameter underlying that again, of the base of the cylinder in yards? Okay, so this question is pretty cool because well, it's not cool. It's actually sucks. All questions stuck on sad. But it's interesting because usually what they do is on these kind of questions, they give you some kind of dimension, maybe they give you the height, maybe they give you the radius, and they asked you to find the volume.

But they're flipping things on you. They give you the volume, and they're asking you to work backwards to find out what the diameter is. Well, if you want to find out what the diameter is, you got to ask yourself, Well, how do I calculate the volume of a right cylinder or a right circular cylinder? Well, do you need to know this? Of course not. Are you crazy?

Of course not. Why? Because the SH t gave you the value. Thank you. gave you the formula in the reference sheet, so just flick to it, and you'll know it. So what it actually is, is the volume is four pi, let me write it down here.

Well, not four or five pi r squared h, that is how to calculate the volume of a right circular cylinder. So that is equal to 72 pi, they told us that was the volume. So what we want to do now is start simplifying until we find out what r is. And once we get that we can find with diameters and they told us up here that the height, which is signified by those arrows, there is eight yards. So if we plug in eight here, we're gonna get four or pi. I don't know why I keep saying four, four pi.

Man, that makes no sense. All right, pi r squared, eight is equal to 72 pi. Now I'm going to divide by pi on each side. So I get eight r squared is equal to 72. Now I'm going to divide by eight on each side. So I'm going to get r squared here.

Equal to nine. And r is equal to what's cube root of nine? Well, that's just three, right? Three times three times three, or three times three is nine, three squared. So my art is three. But are we done?

No, stop, stop, stop, stop, stop, stop. We're not done. We're not done, hold up, hold up, hold up. They even underlined it, and I even underlined it. And I'm going to box it into they asked what the diameter. What did we just find out?

We found out the radius, the radius, so the radius is half of the diameter. So if you want the diameter, let's multiply this guy by two. And that'll give us six. Now that's our diameter. There you go. Now you can stop.