science in this video I'd like to go over how to calculate density mass or volume first you can see I have a triangle here and the formula for density is equal to density is equal to mass divided by volume and you can use this triangle and remember you're going to the DMV so it's going to be a D em V and this is density so if you need density its mass over volume if you need volume its mass divided by density and then if you need mass its density by volume and I'll work an example for each of these okay so the first example is this let me move this up just a little bit triangle will go out of the way but I'll draw smaller ones is this a cake has a mass of 500 grams and volume of 250 centimeters q what is the density of the cake so in the first example I'm going to draw very small remember it's D em V and I know that's a little small but I think it'll work so let's see what we have yeah we're looking for density is equal to we have the mass of 500 grams so the mass is here so it's gonna go on top 500 grams and then volume which is the the V right here is 2500 and that is centimeters cubed and so when you divide 500 by 2500 that equals 0.2 and you're left with grams per centimeters cubed okay that's the first example of density okay the next next example again I'm gonna draw a little triangle d m/v it has we're looking for a solid block of wood has a mass of six grams and a volume of 12 centimeters cubed what is the density of the block of wood so again I'm looking for density the mass which goes here is 6 grams the volume it's 12 centimeters cubed when you divide 6 by 12 that gives you point 5 and again you have grams per centimeters Q okay so now we'll see how this triangle can come in to business when we work a couple other type of examples and so me pull this down and it says this the density of a substance is 8 grams per centimeters cubed if a sample of the substance has a volume of 25 centimeters cubed what is its mass so again I'm gonna go to the DMV the m/v okay and I am looking for mass mass is here so it's just density times the volume so I'm gonna put mass is equal to D times B now all I have to do is plug in the numbers well I know that it says the density is 8 grams per centimeters cubed times and the volume is 25 centimeters cubed okay and so when you multiply that that gives you 8 times 25 is 200 now what do we do with our units okay well if you want to look at this this is grams over centimeters cubed and this would be centimeters cubed over one these cancelled and you're left with grams over one or grams so it becomes 200 grams and make sure that the units are done properly and finally you have a weight with a mass of 820 grams the density of the weight is 5 grams per centimeters cube what is the volume again we'll go back to this we're trying to find volume and it's mass divided by density so V is equal to M over D so let's just plug in the numbers okay I have a mass of 820 grams have a density of 5 grams per centimeters cube okay and then when I divide 820 by 5 that equals 160 for the grams cancel and I'm left with centimeters cubed so the volume is 164 centimeters cube so there we go remember you go to the DMV the D em V and that's density mass volume and you can calculate all three of those using the triangle thanks for watching and moomoomath uploads a new math and science video every day please subscribe and share