Hi, I'm Cathy with Level Up RN. In this video, I will be going through several examples of converting between the metric system and the household system. And I'll be solving these problems using two different methods which include dimensional analysis and ratio and proportion. You can find all the information that I'll be covering in this video in our Level Up RN dosage calculation workbook. If you are in nursing school, then you know how important it is to master dosage calculations, and our workbook will help you do just that. In a nutshell, our workbook contains all different types of dosage calculation problems that you are likely to encounter in nursing school. And we demonstrate how to solve each problem using multiple methods so you can pick the way that makes the most sense to you.
In this video, I am going to work through example problems of converting from the metric system to the household system or vice versa, from the household system to the metric system. In order to be able to do this, you have to memorize these conversion factors over here. So one kilogram equals 2.2 pounds. 30 milliliters equals one fluid ounce. 15 milliliters equals one tablespoon. 5 milliliters equals one teaspoon, and 2.54 centimeters equals one inch. You have to know these. So we're going to work through four example problems, and I'm going to work through these problems using dimensional analysis as well as ratio and proportion.
So our first problem, example problem number one, has us converting 132 pounds into kilograms. So with dimensional analysis, we want to first just write down kind of what our current units of measure are, and then we want to multiply times the appropriate conversion factor. So in this case, this is the one we need. So we've got 1 kilogram equals 2.2 pounds. And I set it up just like this so that my pounds can cross off. And when I multiply this out, I will end up with kilograms. So in this case, we end up with 60 kilograms. And this is something you have to do all the time in nursing school with dose calculation problems. You're going to need to convert from pounds to kilograms, so you definitely need to know how to do this. All right. Let's solve the same problem using ratio and proportion. So we know that 1 kilogram equals 2.2 pounds, and we want to know how many kilograms are in 132 pounds, right? X is our unknown value. So we're going to cross-multiply here. So 1 times 132 is 132. And then we have 2.2 times X, and then we're going to solve for X. So 132 divided by 2.2, that gives us 60. So same answer here, 60 kilograms. This takes a few more steps than dimensional analysis, but if you're into algebra, this might be your method. Also, we have some flexibility as far as how we set up this ratio versus dimensional analysis where we really don't have that flexibility. We need to make sure our units cross off, and we're left with the units that we are looking for.
All right. Let's work through our second example problem. With this problem, we want to convert seven fluid ounces into milliliters. So let's solve this with dimensional analysis first. So we have seven fluid ounces, so that's our current unit of measure. And we want to multiply this times the right conversion factor. So you can see that we have this conversion factor here, which will help us get to milliliters. So we're going to multiply this times 30 milliliters over one fluid ounce. And I set it up this way so that my fluid ounces will cross off. I'll multiply this out, and I end up with 210 milliliters. And we can solve the same problem using ratio and proportion. So with that, we set up our known ratio. So 30 milliliters equals one fluid ounce. And on this other side, we are looking for the milliliters, and how many milliliters are in seven fluid ounces, okay? And then we would just cross-multiply again here. So X times 1 is X, and then we have 30 times 7. So X equals 210 milliliters.
All right. Here's our third example problem. With this problem, we want to go from 40 milliliters to teaspoons. So with dimensional analysis, we're going to write down our current units of measure, which is 40 milliliters. And we need to use this conversion factor here. So 5 milliliters equals one teaspoon. So one teaspoon over 5 milliliters. That will allow us to cross off our milliliters. And when we multiply this out, we end up with eight teaspoons, okay? Now, let's do the same thing with ratio and proportion. So 5 milliliters is in one teaspoon, and we want to know for 40 milliliters, how many teaspoons is that? So we would cross-multiply here. So we have 5 times X. So 5X, 1 times 40 is 40. And then we're going to solve for X. So X equals 40 divided by 5, X equals 8 teaspoons.
All right. For our final example problem of converting between the metric system and the household system, we have 5'4" that we want to convert into centimeters. And we need to round our answer to the nearest whole number. So we're going to tackle this in two steps. We need to first make this number here into just inches, and then we can convert from inches to centimeters. So we want to convert 5 feet into inches and then add in those extra 4 inches. So with dimensional analysis, we have 5 feet, and there are 12 inches in one foot. And if we multiply this out, we end up with 60 inches. We can solve this as well with ratio and proportion. So with that, we have 12 inches, and one foot equals 5 feet, and we want to know how many inches. And so we would cross multiply here. X times 1 is X, 12 times 5. And again, we end up with 60. So 5 foot equals 60 inches, but we need to add those additional 4 inches in, so it's 64 inches.
Now we need to convert 64 inches into centimeters. And this is the conversion factor that we're going to be using to do that. So I'm going to erase my work here that allowed us to get to 64 inches. So using dimensional analysis, I write down my current units of measure, which is 64 inches. And then I multiply this times the conversion factor here. And I want to make sure I'm putting centimeters on top because that's what I'm looking for, and inches on bottom so that my inches will cross off. And then if I multiply this out, I end up with 162.56 centimeters. But you'll notice that our instructions said to round to the nearest whole number, so I am going to round this up to 163 centimeters. And we can do this same problem using ratio and proportion. So with ratio and proportion, I know that 2.54 centimeters equals 1 inch, and I want to know how many centimeters are in 64 inches. So I'm going to cross multiply here. 1 times X is just X. And then we have 2.54 times 64. This again, equals 162.56, but we want to round to the nearest whole number, so that will be 163 centimeters.
