SAO PAULO (Dow Jones)-The board of Gerdau SA (GGB, GGBR4.BR), Latin America's biggest steelmaker, approved a proposal to buy the one-third stake of its U.S. subsidiary Gerdau Ameristeel Corp.'s (GNA) that it doesn't already own for up to $1.7 billion, the company said Tuesday in a statement. Earlier in June, Gerdau announced that it will offer $11 per outstanding Ameristeel share. Gerdau already owns 66.3% of Ameristeel's shares. Gerdau, which has benefited recently from a recovery in economic activity, said it intends to fund the deal through existing cash resources and financing. -By Rogerio Jelmayer, Dow Jones Newswires; 55-11-3544-7071; rogerio.jelmayer@dowjones.com