1. The problem statement, all variables and given/known data http://www.geocities.com/zakcapriturbo/bourdon_diag02.jpg A pointer is connected to an arm that moves along a single axis via a pinion gear wheel and gear quadrant. A displacement of the arm (x) results in an angular movement of the pointer (X3). Knowns: Effective radius of the pinion wheel (R3) and gear quadrant (R2) Distance between the quadrant and arm pivot point (R1) Displacement of arm (x) Question: How can I work out angular movement X3 using only the above information? 2. Relevant equations None but I know it's just an amplification factor...see below 3. The attempt at a solution Well, this has confused me because some movements are angular and some linear. I have worked on similar problems before but the movements were all linear, making it simple to derive an amplification factor. I've scoured the web for tips and hints on this and cannot find anything. Really, I just need some help to get going!