San Francisco ? Yahoo Inc. became Microsoft Corp.’s takeover prey largely because Google Inc. established such a commanding lead in the Internet’s lucrative search advertising market.

But after eluding Microsoft’s grasp, Yahoo is now turning to Google to help squelch a rebellion among its shareholders who believe it should have accepted Microsoft’s $47.5 billion buyout offer while it was still available last month.

Yahoo announced its decision to let Google handle some of its advertising sales late Thursday, just a few hours after revealing it unsuccessfully tried to persuade Microsoft to renew its previous offer of $33 per share. The snub caused Yahoo to conclude that there is no hope for any kind of deal with Microsoft.