So we understand that density is just mass per volume. Now we're going to take that idea of density and apply it to geometric objects. We're going to say here when given the mass of a geometric object, you can relate it to its volume and density. Our typical geometric objects are a sphere, a cube and a cylinder. Each one of them has their own volume equation, which when later on relate to density if we wish.

So here we have a sphere. Now in this sphere we have R radius and remember the radius is just the distance from the center to the edge of the sphere. When it comes to a sphere, its volume equation is V=43πr3. Notice none of these formulas are going to write are in purple boxes, which means you don't need to commit it to memory. Typically when it comes to volumes of geometric objects, your professor will give it to you within the question or on a formula sheet.

Now when it comes to a cube, a cube has all these sides, which we label a. In a cube we assume that they're all of equal length. As a result of this, the volume of a cube is equal to V=a3, where again A is equal to the length or the edge of that cube. Finally, we have a cylinder and in the cylinder we have to take into account 2 variables. We have the height of the cylinder, and we have of course again the radius of the cylinder. Taking these two into perspective, when it comes to a cylinder we have V=πr2h.

So now we're going to take a look at density questions which relate to these different types of geometric objects.