Perimeter of curved shapes
Saturday, 08 August 2009
This week, Year 9 were looking at finding the perimeter of shapes that include curves (parts of a circle).
Along the way, I remembered I had this photo of a playground in my local area.
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Click image for a larger version
Here it is in Google Maps (sorry, no link to the actual site):
From my notes when I took the photo, the radius of the circle is 11.75m.
How could you use this?
- I used it as a review the day after we had worked out how to calculate the perimeter of part of a circle. The scenario set was “how does the builder plan for the number of bricks required?”
- If I had remembered I had the image before we did the lesson, I would have used it as an introduction – “how are you going to solve this problem?”
Having only got a projector in my classroom this year, this is the sort of stuff I’ve been wanting to do since I started teaching.
Feel free to take this image and use in your own classroom. Obviously for a more senior/advanced class you could calculate other things like the length of an arc formed by the two seats.
Download: Photo - Curved Wall (ZIP 736 KB)
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Comments
Great use of photo + google maps! It can be hard to find circle applications. Thanks for sharing. I think throwing it on the screen as an unfamiliar problem is a good instinct.
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