Question

已知:如图∩DAC=∩B求证∩ADC=∩BAC

Answer 1

1.∵∠ DAC = ∠B,∠C = ∠C,△ABC中,∠B+∠C+∠BAC = 180°△DAC中,∠DAC+∠C+∠ADC = 180°∴ ∠ADC = 180° - (∠DAC + ∠C) = 180° - (∠B + ∠C) = ∠BAC 得证2.是要求周长的取值范围嘛?假设BC = 4x 则 AC = 3...