Cross sections are line graphs that show a sideways view of a landscape. They can show features such as hills and valleys, or depths, such as the depth of a river.

Calculate resistance and cross section area, A, in mm 2 (A = \(\frac {{\pi }d^2}{4}\)). Plot a graph of resistance, R, in Ω on the y-axis against cross section area, A, in mm 2 on the x-axis.