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Similar polygons vary directly with each other. They have the same scale.
Something I notice about the polygons is that both of the sides are decreased by 10.
40-30= 10 and 28-18=10
Try to find the scale.
40/28= 1.42857....
30/18= 1.666666777
I would say these are not similar polygons. They do not share the same scale.
I hope this helps!
~kaikers
