Answer:
Volume = 684 in^3
Step-by-step explanation:
To start, the equation for Volume = L*W*H
So, lets begin with the cube on the top, all of its sides are 6 inches in length, so do:
6*6*6 to get the volume of just it
216
Next. lets get the rectangular prism.
6*6*13
468
Last, combine these.
684 in^3
70% * x = 77
(70/100) * x = 77
Times both sides by 100/70 to cancel the left side
x = 77 * (100/70)
x = 110