<human>: Objective: How can you measure something to see if it is about 6 inches long without a ruler?

Which of the following solutions is more sound in terms of naive physics reasoning?

OPTIONS:
- Place a Dollar (Or other American Bill) beside the item.  A bill is about 6 inches - 2 of them is about a foot.
- Place a quarter (Or other American coin) beside the item.  A coin is about 6 inches - 2 of them is about a foot.
<bot>: Place a Dollar (Or other American Bill) beside the item.  A bill is about 6 inches - 2 of them is about a foot.