A 20m Fink Truss are spaced at 'S' meters o.c. the purlins are made up of C10X20 sections and are spaced 1.1967m on centers. The truss has a height of 4m. Roof LL is 'RLL' N/m2 of roof surface and roof covering is assumed to be 'RDL' N/m2 of roof surface. Determine whether the purlins are adequate to carry such loadings. Fy 248 MPa. C10X20 properties: w=29.76kg/m, A=3787.09mm², Ix=32.84x10^6 mm^4, ly=1.17x10^6mm^4, Zx=317.91x10³mm³, Sx=258.92x10^3mm³, Zy=44.25x10³mm³, Sy-21.47x10^3mm^3. determine if the section is adequate to carry the loading considering the sag rods are placed at the midspan at what is the required diameter of the sag and tie rods.