Question 1
You probably agree that it's fairly obvious that the stack on the right is slanted, while the stack on the left is straight up and down (more or less).
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Question 2
The stack on the left resembles a cylinder. It might help to wrap the coins in a paper casing to better see this.
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Question 3
The heights of each stack appears to be the same. This is assuming both stacks have the same number and type of coins.
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Question 4
The two stacks have the same volume. This may seem a bit strange, but if both stacks have the same number and type of coins, then each of the individual coins has the same volume. When put together, the overall 3D solids will have the same volume as well. It doesn't matter if we slanted one of the stacks or not.