Spherical Geometry: Do Parallel Lines Meet?

We live on a sphere (or an approximate sphere) called Earth. Have you ever wondered what is a straight line on a sphere? Or whether there are parallel lines on a sphere? Or about the sum of the angles of a triangle on a sphere?

We interviewed Dr. Megumi Harada (McMaster University) on this theme, and you can view the nine video clips of her interview by clicking on the titles at the bottom of the interactive below. The order of the video clips is left to right. There are also three other videos that you can view, by clicking on the titles in the upper right-hand corner of the interactive.

You may want to view and print an activity about spherical geometry; and also view and print our poster about spherical geometry.