Question 595859
You think of it like this.


Say you filled the cone up with water. If you dumped the water from the cone into a rectangular container that can also hold 50 blocks (not at the same time) that are 1x1x1 inch, and the water filled to the top of this rectangular container, then you can say with certainty that the volume of the cone is 50 cubic inches.


Alternatively, you can think of it as having 50 ice cubes that are 1 inch in length, 1 inch in height, and 1 inch in depth. If you melted those cubes and placed them into the cone (without spilling water), then you can be certain that the cone is 50 cubic inches (again, the water must completely fill it).