1 very lame question ^^ (1 Viewer)

[tau281290]

To round 20.0855... to 3 significant figures is 20.1??

Why? It should be 20.09 when the 0 between the decimal and 9 does not count.

So is both correct or what? Because 20.09 is to 3 sig fig, so is 20.1

Sorry to ask this lame question lol

 

[Iruka]

When figuring out significant figure problems, zeros count when they are between non-zero numerals.

One of the best ways to answer sig fig questions is to convert your answer into scientific notation.

 

[henry08]

Yes, 20.1.

 

[vmoore]

to be perfectly honest with you, it was questions like this in 2unit which made me do 4unit.

im sorry, i crnt help but i think its 20.1

 

[ratcher0071]

To round 20.0855... to 3 significant figures is 20.1??

Why? It should be 20.09 when the 0 between the decimal and 9 does not count.

So is both correct or what? Because 20.09 is to 3 sig fig, so is 20.1

Sorry to ask this lame question lol

IT IS 20.1 not 20.09

20.1 : 3 sig figures
20.09 : 4 sig figures

 

[lolman12567]

a general rule that our teacher told us was that find the first whole number and count on how many sig. figures the question specifies, i think that works most of the time

so for 20.1234145 to 8 sig figures would be20.123415

 

[aimhigh10]

20.1


because all numbers between the first non-zero digit and the last non-zero digit are counted as being significant figures (including the first and the last).

 

[PC]

Rules for Significant Figures:
1. All non-zero digits are significant.
2. The first non-zero digit is the first significant figure.
3. All zeros after the first significant figure are also significant.
4. Trailing zeros may or may not be significant.

For example:
The population of Australia is (something like) 21,376,842. Rounded off to 3 sig figs this would be 21,300,000. We need the extra zeros to hold the place values. This number is clearly an approximation, so in this case the zeros at the end are not significant.
The width of a football field is 70 m (exactly). So in this case the zero at the end IS significant because it hasn't been rounded off yet.

Significant figures are really easy if you get your head around scientific notation.

For example, write 0.00004562 in scientific notation, correct to 2 significant figures.
First do the sci notation: 4.562 x 10^-5
See how the first 5 digits, the zeros, are not significant!
Then round off: 4.6 x 10^-5

Hope this helps

 

[duy.le]

For example, write 0.00004562 in scientific notation, correct to 2 significant figures.
First do the sci notation: 4.562 x 10⁵
See how the first 5 digits, the zeros, are not significant!
Then round off: 4.6 x 10⁵

Hope this helps

isnt it 4.562 x10^-5
and hence 4.6 x10^-5

=p(sorry had to do it)

 

[PC]

Isn't that what it says?

Ta.

 

[jesuslovesyou]

you count significant figures from the first non zero digit eg. 0.0046789 to two sig fig would be 0.0047. you count any digit whether it be a zero or not after that.