00:02
Hi there.
00:03
This question deals with significant figures and we want to know which of these numbers represents a number with four significant figures.
00:11
So each of these should be representing measurements because it's measurements that have significant figures.
00:17
And when determining the number of significant figures, our first rule says that non -zero digits are significant, all non -zero digits.
00:27
So that means letter a has three significant figures because all of those non -zero digits.
00:32
Zero digits are significant.
00:37
The same is true if letter b.
00:39
It also has three sigphigs.
00:44
All right.
00:45
Our next two options have some zeros.
00:47
We know that the non -zero digits in each of these are significant.
00:52
But now we need to think about the zeros.
00:55
Well, one of the rules tells us that the zero in front of a decimal point is not significant like this.
01:03
When it's just a zero in front of a decimal of a decimal number, it is just a formality that we write to let people know that, hey, a decimal is coming next.
01:13
Okay, the next zero we see here, thinking about these as measurements, having that zero in front of the measurement would be no different than saying, than measuring something to be, maybe you measure something to be 25 meters in length.
01:31
You would not put a zero in front of that.
01:33
That would not be part of your measurement.
01:35
The same thing is happening here...