Comparing scales with different units
About this video
To compare two maps drawn at different scales, imagine the same real object on both. Karina's scale (1 cm to 3 km) makes each centimeter represent less than Benji's (1 cm to 5,000 m = 5 km), so Karina needs more centimeters and her map is larger.
You'll be able to
- convert kilometers and meters to compare two scales.
- decide which of two scales makes a larger map.
- explain my reasoning using a made-up example distance.
Key words
- scale
- A rule like 1 cm to 3 km that tells what real distance one map length stands for.
- kilometer
- A unit of length equal to 1,000 meters.
Transcript
- [Instructor] Told that two students each draw a map of the same mountain range, but they used different scales. Karina used a scale of 1 centimeter to 3 kilometers. Benji used a scale of 1 centimeter to 5,000 meters. Whose map is larger? Pause this video and have a go at this.
All right, now, the way I think about it is, I first think about the mountain and then I think about how big would that mountain look on each person's map? And you say, well, we don't know how big the mountain is. Well, let's just make up a mountain. And let's just say that that mountain, let's say that that mountain, that's the mountain right over here, and let's say that, or it's a mountain range, but let's just draw one of the mountains.
And let's say that this right over here, this distance right over here is 5 kilometers, which is the same thing, of course, as 5,000 meters. Now, this mountain, it's width on Karina's map, how big it would it look? On this map right over here, you have 1 centimeters to every 3 kilometers.
So, a centimeter on her map would go about 60%. It would go three-fifths of the way. So, in Karina's map, this mountain would be about a little over a centimeter. So, over 1 centimeter for that mountain in Karina's map. And what about in Benji's map? Well, in Benji's map, this mountain would be exactly 1 centimeter because you have 5 kilometers, same thing as 5,000 meters.
That is 1 centimeter on Benji's map. So, in order to draw this mountain, you're going to have to use more space on Karina's map. Each centimeter to each centimeter represents less on her map. So, you're gonna need more centimeters to cover the same distance. So, Karina's map is larger.
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