其实这道题只要认真想想就会很容易解的、
∵ad平分∠bac
∴ED=CD(角平分线上一点到角两边的距离相等)
∴ED=4cm(等量代换)
S△ABD=S△AED+S△EBD
=1/2(AE×ED)+1/2(EB×ED)
=1/2ED×(AE+EB)
=1/2ED×AB
=1/2×4×10
=20(cm²)
其实这道题只要认真想想就会很容易解的、
∵ad平分∠bac
∴ED=CD(角平分线上一点到角两边的距离相等)
∴ED=4cm(等量代换)
S△ABD=S△AED+S△EBD
=1/2(AE×ED)+1/2(EB×ED)
=1/2ED×(AE+EB)
=1/2ED×AB
=1/2×4×10
=20(cm²)