设一个边的电阻为R，则RDAC=RDBC=32R，C、D两端的电阻为RDAC和RDBC并联，RCD=12×RDAC=12×32R=9Ω，∴R=12Ω；AB两端的电阻是RAB和RACB并联，RAB=R=12Ω，RACB=2R=24Ω，R并=RAB×RACBRAB+RACB=R×2RR+2R=23R=23×1...