This week’s SUMS talk is by Cambridge student Rachel Wong. Pizza available afterwards. Abstract: What’s your favourite centre of a triangle? Would it happen to be the orthocentre, or maybe the centroid? Back in 1765, Euler proved that several triangle centres in fact lie on the same line, which is now named after him. In this talk, we’ll look at what some of these centres actually are, and then spin, flip and zoom into triangle transformations to show how they’re all connected (and collinear)!