Scale Drawings

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Scale Drawings

Mrs. Schmidt's 7th Grade Math Tutoring · ⏱ 2:35 · 104.9K مشاهدة · 6 years ago

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Let's do an example of scale drawings. Scale drawings are part of proportional relationships and scale drawings are used when we are trying to draw something that in real life is much too big to draw to actual size. So the scale of it's too big, we need to shrink the scale down to something so we can actually work with it. So the most common way we see this is in architecture. When somebody's planning building, to build house, to build mall, anything like that, they're not going to find massive piece of paper and roll it out over football fields and try to draw it to the actual size that it is. That would be crazy. What they're going to do is they're going to shrink it down to smaller scale so they can plan it and then they'll know what their scale is will equal what it's going to be when it's bigger. This needs to be really precise and accurate so that your windows fit and your doors fit and your stairs go in the right way. So these numbers really need to be precise. So the scale needs to make sure it's the same. So let's look at this problem that we have. Here's my regular sized house. This is the big house and it's certain number of feet, but we don't know how many feet it is. But we know that the little drawing that they did of it is 8.5 inches and we are told that our scale is for every 2 inches, it's 5 ft. So when set up proportion, first draw my words. So have my words contain my units of measurement. So in this problem, have inches and I'm comparing those inches to feet. So now I'm going to draw my skeleton. And my scale is 2 inches to 5 ft. So I'm going to make sure 2 lines up with inches and 5 lines up with feet. Making sure everything is matching is really important in all proportional relationship problems. All right, now I'm going to look at what my problem gave me, okay? We're looking for feet. We don't know feet yet, but they gave us 8.5 inches. So I'm going to line that up with inches. And now I'm going to do my fish or cross multiply and divide. I'm going to do 8.5 * 5 divided by 2 equals and that equals 21. 25. So what does that mean? So that means that if my scale is for every 2 inches, you have 5 ft in real life and this little drawing is 8.5 inches, that means in real life my house is 21. 25 ft tall. And that is scale drawings. You have some more examples in your notebook if you need to look at them and some definitions in there that is helpful for scale drawings, too.