If a sword's blade edge was 5 inches thick to us, but sharp to a giant, how big would the giant and sword be?
Assuming that the giant perceives the sword's blade edge as sharp despite its 5-inch thickness to us, we would need to adjust our perception of the size of the giant and the sword based on the scale of the difference in perception.
If we assume that the giant perceives objects at 10 times smaller than their actual size, then the giant would be 10 times larger than us. Therefore, if the giant perceives the sword's blade edge as sharp, it would likely be around 50 inches thick to the giant.
Similarly, if we assume that the giant is 10 times larger than us, then the giant would be around 50 feet tall. The sword would also be scaled up by a factor of 10, so the giant's sword would be 50 inches thick and much larger in size compared to a regular-sized sword.