# Practice Question: Ratio and Proportion (Nursing)

by Rhonda Lawes

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Slides Nursing Dosage Calculation Ratio Proportion.pdf
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Cheat Sheet Understanding Ratios.pdf
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00:00 Now, I want you to practice. So let's take a look at these. I recommend you pause the video.

00:05 Just work through these on your own with a pencil or some other writing instrument and then come back and watch us go through the answers to check your work.

00:18 Okay, welcome back. We have, is 4:5 equal to 16:20? Or you may say it, is 4/5 equal to 16/20? However you want to is fine.

00:33 Now we know we want to cross multiply, right, that's our goal.

00:36 So now we're looking at does 4:20 equal 5:16? We've just crossed multiply, right, the means and the extremes.

00:48 So 4 times 20 is 80. 5 times 16 is 80. Yes. These are equal.

00:56 Okay, still with us? Let's do the second one.

00:59 Okay. Is 2 times 12 equal to 3 times 6? Remember, we did the cross multiplication.

01:06 Well, 2 times 12 is 24. 3 times 6 is 18. So these are not equal.

01:15 If I used this to figure up a medication dosage, I would be incorrect.

01:21 The patient would not be receiving the appropriate level of medication.

01:25 Now, 5/8 and 10/16. Well that's 5 times 16, does that equal 9 times 10? 5 times 16 is 80. 8 times 10 is 80. So yes, the first and third example are equal. Sweet.

01:41 We did the right type of math to figure out an appropriate medication dosage.

01:46 Middle one? Not equal.

01:48 That's why we'll show you how to check your work and make sure you solve correctly for x in our video series.

01:54 Okay, so looking at these pictures.

01:56 First of all, the steps. What do we go through to make sure the ratios are equal? Well, first you identify the ratio.

02:04 You'll see the picture we have on the left of the three tennis balls and the four Harleys or schnauzers.

02:09 On the right, we've got six tennis balls and 1-2-3-4-5-6-7-8 Harleys.

02:15 Oh my. I cannot imagine. Cuz just leaving with one Harley is enough fun for me.

02:21 This could be written as 3:4 and 6:8.

02:25 So when you're not looking at tennis balls and really cute schnauzers, you'll be looking at medication.

02:31 This is how you'll learn to identify the ratio and to write it out.

02:35 Now once you've identified the ratio, you're gonna set up the proportion.

02:39 So we take what we know and we make it as a fraction to set up the proportion.

02:44 3 over 4, because the left side is the numerator then the semicolon.

02:49 The next number is the denominator, 3/4 equals 6/8.

02:54 Next we cross multiply. 3 times 8 equals 4 times 6. The answer is both 24.

03:02 So yes, the picture on the left and the right and the ratios that we've drawn from those are equal.

03:10 So these are equal and this equals a proportion, we are using the word equal a lot.

03:17 But that's all about what a proportion is.

03:20 Your ability to recognize when a proportion is appropriate and equal.

03:27 That's how we give the correct dosage to our patients.

The lecture Practice Question: Ratio and Proportion (Nursing) by Rhonda Lawes is from the course Dosage Calculation (Nursing).

1. 12:14
2. 24:28
3. 18:22
4. 14:17
5. 16:21
1. 6/21
2. 4/12
3. 3/15
4. 5/17

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