1) Give the mathematical definitions of Ra, R, R and Rmax. Evaluate each surface roughness index using the formulations you have given. You need to establish the centerline (or mean height of nominal values) and re-evaluate all the nominal y values with respect to the centerline to be able to correctly evaluate your surface roughness values. Ra Ra Rz Rmax X value Nominal value Re-evaluated y value X value Nominal value 1 y 0.002 3 2 0.000 0.003 Re-evaluated y value 4 0.002 5 0.004 11 12 13 14 15 y 0.005 0.000 0.003 0.002 0.004 6 7 8 9 0.006 | 0.001 0.005 0.003 16 0.006 17 0.001 18 19 0.005 0.000 (unit: mm) 10 0.004 20 0.004