Two
5 significant figures.
The 7 and the 6.
12.655 cm rounded to four significant figures is 12.66cm
Four.
All three of them are significant figures
How many significant figures are in the measurement 210 cm?
5 significant figures.
There are 4 significant figures in this number.
There are 2 significant figures in this measurement.
4.05 has three (3) significant figures
The 7 and the 6.
There are 3 significant figures
None. The abbreviation cm represents one or more centimeters. In your question there are no numbers associated with the cm unit, therefore there are no significant figures.
You would need to record to the 0.1 cm, then estimate the next significant figure. So you should have a measurement to the 0.01 cm.
12.655 cm rounded to four significant figures is 12.66cm
This has 4 significant figures, and they are 6420
3 of them.