A Simple and Fun Geometry Problem

Here’s a math puzzle about Thanom’s roll of paper. Hmm, perhaps he has made a mess in the kitchen!?

Here’s a hint: a diagram will come in handy …

I recommend you pause the article, grab your pen and paper, and give this a go. When you are ready, keep reading for the solution!

Solution

We are given that the diameter of the roll is 12 and the diameter of the inner tube is 4.

That means they have radii 6 and 2respectively. The area of the inner tube is therefore 2²pi = 4pi. (This is crucial as we will see.)

A Simple and Fun Geometry Problem