AB=AC,BD=BC,且∠A=36°,且AB=根号5+1/2,求AD

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AB=AC,BD=BC,且∠A=36°,且AB=根号5+1/2,求AD

AB=AC,BD=BC,且∠A=36°,且AB=根号5+1/2,求AD
AB=AC,BD=BC,且∠A=36°,且AB=根号5+1/2,求AD

AB=AC,BD=BC,且∠A=36°,且AB=根号5+1/2,求AD
利用余弦定理可知:
BC^2=AB^2+AC^2-2*AB*AC*cosA=2.85,故BC=BD=1.69
CD^2=BC^2+BD^2-2*BC*BD*cosA=1.08,故CD=1.04
所以,AD=AC-CD=1.7