AD=40÷4=10BD:AC=3:4∴OD:OA=3:4AC⊥世派BD∴OD:OA:AD=3:4:5(勾股定理)搜岁贺OD=6,AO=8AC=2AO=16BD=2OD=12菱形ABCD面雀早积=1/2AC*BD=96
AD=40÷4=10BD:AC=3:4∴OD:OA=3:4AC⊥BD∴OD:OA:AD=3:4:5OD=6,雀早AO=8AC=2AO=16BD=2OD=12菱世派形ABCD面积=1/搜岁贺2AC*BD=96