Answer: 120 units3
Step-by-step explanation: When finding the base of a prism, you must always multiply the side with the right angle. So basically, 5 is ignored because it does not have a right angle.
1st step: 3*4=12
2nd step: 12/2=6 (because the tringle which is the base is half a square)
3rd step: 6*20=120
The ending is unit 3 because it is volume. Area is unit 2 and we don't know if the prism is in cm so it is not A, or B, and D is the incorrect answer.
In conclusion:
120 units 3
Hope this helped!
Alin