Calculate mass of lead:
1.00 cm3 lead x 11.4 g/cm3 = 11.4 g lead on one side of balance
To balance that, one needs 11.4 g of iron on the other pan. Calculate volume of iron to give you 11.4 g:
11.4 g iron x 1 cm3/7.87 g = 1.45 cm3 of iron needed
Brain list please