The sudden perception of a connection between ideas is exhilarating. We might call these moments 'Aha!' moments. The purpose of this paper is to demonstrate how several different ideas can come together in Year 12 mathematics. The subject Further Mathematics in the Victorian Certificate of Education (VCE) is the Victorian adaptation of General Mathematics in the Australian Curriculum. The author will explain how three disparate topics (parabolas, simultaneous equations, and linear regression) in VCE Further Mathematics fit together to lead students to arrive at a relational understanding of the regression line, or the line of best fit in the least squares sense. The ideas below may be pertinent to other subjects such as Mathematical Methods and some first year university subjects