RT,
我做过这道题,应该是面积比为1:2吧?由题意知,AB‖OB'∴∠B=∠OB'C又∵∠ACB=∠OB'C∴△ABC∽△OB'C∵S△ABC:S△OB'C=2:1∴BC:B'C=根号2:1∵BC=根号2∴B'C=1∴BB'=BC-B'C=根号2-1