To find the dimensions of steel sections, you can use AISC steel manual. However, the manual does not provide you dimensions for some sections. Alternatively, you can also use AISC Shape Database, which I already uploaded on Moodle (you can also find this excel spreadsheet from AISC website). 

1. Determine the gross and net areas for a 12x5/8 in. plate with two lines of standard holes for % in. bolts.

2. Determine the gross and net areas for an L8x4x9/16 with three lines of standard holes, two in the 8 in. leg and one in the 4 in. leg, for 7/8 in. bolts.