已知○O半径为2,且与○P相切,做个半径为3的○A,使○A与○O○P都想切,这样的圆能做几个?半径为4,2.5,2,1.
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(1)易知:Rt△PAC∽Rt△ABP,PA/PC=AB/APfjPA² =PC*AB=5/2*4=10,∴PA=√10,由勾股定理得:PB=√6,(2)由Rt△PAC∽Rt△ABP,PA/PC=AB/AP,PA² =PC*AB=4X,当PC=X时,PA=2√X,由勾股定理得:AC= √ (4X-X²)hlpPB=2√ (4-X...