Answer : The correct option is (b) 222.0 mm
Explanation :
The following rules are used to round off a number to the required number of significant figures:
(1) If the rightmost digit to be removed is more than 5, the preceding number is increased by one.
(2) If the rightmost digit to be removed is less than 5, the preceding number is not changed.
(3) If the rightmost digit to be removed is 5, then the preceding number is not changed if it is an even number but it is increased by one if it is an odd number.
As we are given, 222.008 mm
According to the rule number 1 of round off the measurement will be, 222.01 mm
But the given measurement in 4 significant digit will be, 222.0 mm or [tex]2.220\times 10^2mm[/tex]
Therefore, the correct option is (b) 222.0 mm
