Frances Newberry is the payroll accountant for Pack-It Services of Jackson, Arizona. The employees of Pack-It Services are paid semimonthly. An employee, Glen Riley, comes to her on November 6 and requests a pay advance of $750, which he will pay back in equal parts on the November 15 and December 15 paychecks. Glen is married filing jointly (box 2 is checked) with three dependents under 17 and is paid $56,000 per year. He contributes 3 percent of his pay to a 401(k) and has $130 per paycheck deducted for a Section 125 plan. Required:
Compute his net pay on his November 15 paycheck. The applicable state income tax rate is 2.88 percent. Use the percentage method in Appendix C to determine the federal income tax.

I can not figure out how to get the federal income tax?