如图，长方体盒子（无盖）的长、宽、高分别是
解：（1）将长方体沿AB剪开，使AB与D在同一平面内，
得到如图所示的长方形， 连接CD，
∵长方体盒子（无盖）的长、宽、高分别是12cm，8cm，30cm，
即DE=12cm，EF=30cm，AE=8cm，
∴CD=
http://www.5xueba.com/uploads/allimg/150929/2045004622-1.png
=
http://www.5xueba.com/uploads/allimg/150929/204500G10-2.png
=
http://www.5xueba.com/uploads/allimg/150929/2045005Y4-3.png
=25cm．
（2）连接AG，BG，
在Rt△BFG中，GF=12cm，BF=8cm，由勾股定理得，GB=
http://www.5xueba.com/uploads/allimg/150929/2045004D3-4.png
=
http://www.5xueba.com/uploads/allimg/150929/2045004E2-5.png
=
http://www.5xueba.com/uploads/allimg/150929/204500G47-6.png
cm， 在Rt△AGB中，GB=
http://www.5xueba.com/uploads/allimg/150929/2045002231-7.png
cm，AB=30cm，
由勾股定理得，AG=
http://www.5xueba.com/uploads/allimg/150929/2045001956-8.png
=
http://www.5xueba.com/uploads/allimg/150929/2045001S5-9.png
=2
http://www.5xueba.com/uploads/allimg/150929/2045004R6-10.png
cm．
http://www.5xueba.com/uploads/allimg/150929/20450045a-11.png
页:
[1]