Question

Determine the number of significant figure in the following.
$3450$ cm

Answer 1

zeroes at the end of a number are also placeholders: $3450$ cm is not the same as $345$ cm. If you want to make zeroes at the end of a number significant, you must use scientific notation. For example, to express $3,450$ cm to 3 significant figures, you must write $0.345\times {10}^4$ cm, not 3450 cm, which is not the same value.

Hence, there are 4 significant figures