



 
Peter, If two polygonal figures are congruent then you can place one exactly on top of the other so that each of the vertices of the top figure is over a vertex of the bottom figure and each of the sides of the top figure is directly over a side of the bottom figure. Since one of your figures has 4 edges and the other has 3 edges you can't arrange them in this fashion and hence they aren't congruent. Harley  


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