Question

如图：矩形ABCD的长AB=30,宽BC=20．

Answer 1

（1）不相似,

AB=30,A′B′=28,BC=20,B′C′=18,

而28 /30 ≠18 /20

（2）矩形ABCD与A′B′C′D′相似,则

A′B′ /AB =B′C′ /BC

则：30−2x /30 =20−2 /20

解得x=1.5,

或

30−2x /20 =20−2 /30

解得x=9．