



 
Hi Abdulganiy, The volume of a pyramid is given by \[\frac{1}{3} \times \mbox{ (the area of the base)} \times \mbox{ (the height)}\] The volume you want is the difference between the volume of the large pyramid with a dark green base and the volume of the small pyramid with a light green base. The only fact you are missing is the size of the small green square. I suggest that you use the fact that triangles $ABC$ and $EDC$ are similar. Penny 



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