Now, I want you to practice. So let's take a look at these. I recommend you pause the video.
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.
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.
Now we know we want to cross multiply, right, that's our goal.
So now we're looking at does 4:20 equal 5:16?
We've just crossed multiply, right, the means and the extremes.
So 4 times 20 is 80. 5 times 16 is 80. Yes. These are equal.
Okay, still with us? Let's do the second one.
Okay. Is 2 times 12 equal to 3 times 6?
Remember, we did the cross multiplication.
Well, 2 times 12 is 24. 3 times 6 is 18. So these are not equal.
If I used this to figure up a medication dosage, I would be incorrect.
The patient would not be receiving the appropriate level of medication.
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.
We did the right type of math to figure out an appropriate medication dosage.
Middle one? Not equal.
That's why we'll show you how to check your work
and make sure you solve correctly for x in our video series.
Okay, so looking at these pictures.
First of all, the steps. What do we go through to make sure the ratios are equal?
Well, first you identify the ratio.
You'll see the picture we have on the left of the three tennis balls and the four Harleys or schnauzers.
On the right, we've got six tennis balls and 1-2-3-4-5-6-7-8 Harleys.
Oh my. I cannot imagine. Cuz just leaving with one Harley is enough fun for me.
This could be written as 3:4 and 6:8.
So when you're not looking at tennis balls and really cute schnauzers,
you'll be looking at medication.
This is how you'll learn to identify the ratio and to write it out.
Now once you've identified the ratio, you're gonna set up the proportion.
So we take what we know and we make it as a fraction to set up the proportion.
3 over 4, because the left side is the numerator then the semicolon.
The next number is the denominator, 3/4 equals 6/8.
Next we cross multiply. 3 times 8 equals 4 times 6. The answer is both 24.
So yes, the picture on the left and the right and the ratios that we've drawn from those are equal.
So these are equal and this equals a proportion, we are using the word equal a lot.
But that's all about what a proportion is.
Your ability to recognize when a proportion is appropriate and equal.
That's how we give the correct dosage to our patients.