Hello, my name is Walter Unglaub, and this is equation for manipulating density. If we want to calculate the density in three dimensions, we have the Greek letter rho, which will stand for the density, and this is defined as the total mass of your object divided by the volume that it inhabits. So, if we wanted to manipulate this equation and we knew the density and the volume was, say we wanted to calculate the mass, then we would simply use algebra to rewrite this expression as the mass is equal to the density times the volume. Or, if we knew what the mass and the density was, we could solve for the volume by simply dividing both sides by the density, so we would have the mass divided by the density rho. Now, as a simple example, let's say we know the mass of our object, it's equal to a hundred kilograms, and we know the volume of our object, the volume v is equal to 10 meters cubed, then we would use this equation to solve for the density. So the density of three dimensions would be rho is equal to the mass, a hundred kilograms, divided by the volume, 10 meters cubed, and this would simply be equal to 10 kilograms per meters cubed. My name is Walter Unglaub, and this is equations for manipulating density.