So we understand the density is just mass per volume. Now we're gonna take that idea of density and apply to geometric objects Were going to say here when given the mass of a geometric object you can related to its volume and density are 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 our radius. And remember, the radius is just the distance from the center to the edge of the sphere. When it comes to a spear, its volume equation is volume equals 4/ times pi times radius. Cute notice. None of these form those were 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, 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 voluble cube is equal to a cube 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 two 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 volume equals pi times, radius squared, times the height. So now we're going to take a look at density questions which relate to these different types of geometric objects.