Answer: E. 6
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Explanation:
The rectangular prism (aka rectangular block) has dimensions 2, 4 and 3. You can say they are the length width and height. The volume is 2*4*3 = 24 cubic cm.
The trapezoid's volume is found by multiplying the area of the trapezoidal face by the depth of 3 cm. Let's find the area of the trapezoid first
A = area of trapezoid
A = height*(base1+base2)/2
A = 2*(4+2)/2
A = 6
Then we multiply this with the depth of 3 cm to get 6*3 = 18 cubic cm
Lastly, we subtract the two volumes
difference in volume = (rectangular block) - (trapezoidal block)
difference in volume = 24 - 18
difference in volume = 6 cubic cm
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An alternative is to find the volume of each triangular piece on the left and right sides. Then add up those portions to get the answer. In a way, you can think of those triangular wedges as empty space.