Visit the website for Federation of Tax Administrators (www.taxadmin.org) under the Taxpayers & Tax Preparers menu, and use the State Tax Agencies link to go to the Illinois Department of Revenue website. Locate a copy of the Corporate Income and Replacement Tax Return (Form IL-1120), scrutinize Step 4, and describe how Illinois’s apportionment percentage is computed. Return to the FTA website and link to the Arkansas Department of Revenue website. Locate a copy of the Arkansas Corporation Income Tax Return (Form AR 1100 CT), scrutinize Schedule B, and describe how Arkansas’s apportionment percentage is computed.