Question

初二数学菱形的性质和判定

Answer 1

2、

AD=2AB,BM=MD

AB=(AM+MD)/2

AB²+AM²=BM²

[(AM+MD)/2]²+AM²=MD²

5AM²+2AM*MD-3MD²=0

(AM+MD)(5AM-3MD)=0

∵AM+MD>0

∴5AM-3MD=0

AM/MD=3/5