在三角形ABC中 AB=AC 角A=36度 BD平分角ABC交AC于点D 证明1.BC=BD=AD 2.BC方=CD乘AC

证明：∵AB=AC ∠A=36°∴∠ABC=∠C=(180°-36°)/2=72°∴BD=AD∴∠ABD=∠DBC=72°/2=36°∴∠BDC=180°-∠DBC-∠ABC=72°∴BC=BD∴BC=BD=AD(2) ∵∠ACB=60° ∠A=∠DBC=36°∴△ABC∽△BDC∴BC/DC=AC/BC∴BC²...