六年级数学一个边长为1米的正方形
┌──┬──d─┐
│ │ │
│ │y c
│ ├┐x │
├──┴┼─ ─┤
│ │ b
└───┴─a─┘
如图
ab=0。 1``````````````````````````````````(1)
(1-a)b=0。2``````````````````````````````(2)
cd=0。4-----------(1-b)d=0。 4`````````````(3)
(1-d)c=0。3-------(1-d)(1-b)=0。3`````````(4)
由(1)(2)得b=0。3,----a=1/3,c...全部
┌──┬──d─┐
│ │ │
│ │y c
│ ├┐x │
├──┴┼─ ─┤
│ │ b
└───┴─a─┘
如图
ab=0。
1``````````````````````````````````(1)
(1-a)b=0。2``````````````````````````````(2)
cd=0。4-----------(1-b)d=0。
4`````````````(3)
(1-d)c=0。3-------(1-d)(1-b)=0。3`````````(4)
由(1)(2)得b=0。3,----a=1/3,c=0。7
代入(3)得d=4/7, x=(1-a)-(1-d)=2/3-3/7=5/21
阴影部分是(5/21)^2=25/441平方米。
。收起
