GIRL 1: (singing) When I was looking for a shape that is completely round, I saw a sphere over here, and this is what I found. I found a marble and a ball of wool, a football I could kick.

When it comes to the photographic image, rectilinearity is taken as a given — but it wasn’t for George Eastman, the founder ...

This is from the series: Let's Do Maths. This clip could be used as a lesson starter and as an introduction to measuring distance round a given shape with missing information. Calculating ...