I WILL GIVE 20 POINTS TO THOSE WHO ANSWER THIS QUESTION RIGHT NOOOO SCAMS AND EXPLAIN WHY THAT IS THE ANSWER

Answer:
its 84!
Step-by-step explanation:
volume of a rectangular prism is length * width * height, since the shape is 3D, or multi-demensional. you take all three numbers and multiply them together :) in this case its 7, 3, and 4. 4 * 3 is 12, and 12 * 7 is 84 :)