Answer:
I think the answer is BD ≅ CE
The volume becomes 1/3 of the original. With a rectangular base, volume of a pyramid is V=(length*width*height)/3. Cutting the height to 1/3 of the original length will make the total volume 1/3 of the original volume.
The Answer is 3
All you need to do is multiply 7 and 1 then divide.
I was to tired to write it down
Notice the picture below, see the length "l"?
well

solve for "w", to find the width,
what's the length? well, l = 11/4 w