The figure is just 3 cubes stacked on top of each other.
The first cube is 2 x 2 x 2, meaning its volume is 8 cm^3.
The second is 7 x 7 x 7, so it's volume is 343 cm^3.
Finally, the bottom cube is 8 x 8 x 8, making its volume 512 cm^3.
Now, we add up the volumes, giving us a total of 863 cm^3.
