Unraveling Circles (K-12) [video]

We use cylinders and circles around the house all the time like cans, tortillas, and rolls of paper towels, but what secrets do these shapes hold if we unravel them? And how many ways can we do this? What shape will a cylinder make if you lay it flat? It probably depends on how you cut it! How long is the strip of paper towels or toilet paper if you unravel a whole roll? What about if you stack it? And you can do the opposite too: how tall or wide will the cylinder you get from rolling up a yoga mat be? How about two yoga mats stacked on top of each other?

And let’s not let circles behind. If you cut a spiral, you can unravel it. How long will it become? Can a tortilla be cut into a single strip that reaches across your table?

What other circles and cylinders around your house can you unravel? How can you make your best estimates for these situations? How can you measure the results?

This lesson is adapted from the lesson Unraveling Circles, in book 7 of the Mindset Mathematics series.