1. The problem statement, all variables and given/known data A material of resistivity p is formed into a solid, truncated cone of height h and radii r_1 and r_2 at either end. Calculate the resistance of the cone between the two flat ends. You can find my awful sketch as a thumbnail. 2. Relevant equations R=pL/A ,where p is resistivity. 3. The attempt at a solution I know I need to calculate dR=(p*dy)/(pi*r^2). But I don't know what is r as a function of y.