Part-to-part ratio models
About this video
The video counts 6 circles and 10 squares and describes the ratio in several ways: for every 6 circles there are 10 squares, for every 10 squares there are 6 circles, and, grouping into two, for every 3 circles there are 5 squares. It then picks the two correct statements and explains why a swapped ratio is wrong.
You'll be able to
- describe a ratio from a diagram in words, in either order.
- find an equivalent ratio by splitting both quantities into equal groups.
- spot a ratio statement that has the quantities swapped.
Key words
- ratio
- A comparison of two amounts, like 6 circles for every 10 squares.
- for every
- A phrase used to describe a ratio, saying how many of one thing go with how many of another.
- equivalent ratios
- Ratios that describe the same relationship, like 6 to 10 and 3 to 5.
Transcript
- [Instructor] We're told to select all statements that correctly describe this ratio relationship between the circles here and the squares here. So pause this video, have a go at that by yourself before we do this together. And they say to pick two answers. So before I even look at these choices, let's see what we have going on here.
We have 1, 2, 3, 4, 5, 6 circles, and we have 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 squares. So one way to think about it is, for every six circles we have 10 squares. So let me write that. For every six circles, we have 10 squares. We could also write it the other way around.
We could say, for every 10 squares we have six circles. Or another way to think about it is, because both of these could be divided into two groups. So we could also say for every three circles we have five squares. For every three circles, we have five squares.
So it could also say, for every three circles, we have five squares. Now, let's look at the choices here. For every five squares, there are three circles. Well, that's just saying this the other way around. If for every three circles you have five squares, and it's also true that for every five squares you have three circles.
So I like that choice. For every circle there are 10 squares. No, that's clearly not the case because for 10 squares we have six circles, not just one. So let's just cross that one out. There are 10 squares for every six circles. Well, that's just another way of saying what we set up here.
10 squares for every six circles. So I like that. And that's exactly what's drawn out here in this diagram. So this last one should be wrong, but let's just double check. For every three squares there are five circles. So this is tempting 'cause I see that three and five there, but it's swapped around.
We said for every three circles, for every three circles, there are five squares. So that's why we would not pick this last choice, but we're done choices A and C.
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