Question

Round off each of these measurements to three
significant figures.
a.98.473 L
b.0.000 763 21 cg
c.57.048 m
d. 12.17°C
e. 0.007 498 3 * 10^4 mm
f. 1764.9 mL

Answer 1

98.5, .001, 57.0, 12.2, .007, 176, This could be what they are asking for, although it is more common to round to three significant figures when using multiple decimal placeholders. I am not a fan of using significant figures. Generally common sense will tell you how many places to keep, depending on how precise you must be, and what you are measuring or looking for. Anyone else with more experience with sig figs help out on this one.

Answer 2

im not exactly sure on what to even do with this.....

Answer 3

Basically you want to keep just three numbers (and leading zeroes don't count as those numbers)

eg.
1.4145 would become 1.41

89.784 would become 89.8 (you round up the same way with decimals)

0.00000000738012 would become 0.00000000738 (the zeroes ahead of 738 don't count)

Answer 4

well that is just plain confusing

Answer 5

It's not, it's similar to just rounding to however many decimal places. except you only want three numbers.

Answer 6

so
a)98.5 L
b)0.001 cg
c)57.0 m
d)12.2 degrees C
e)0.007 mm
f)176 mL


do i have to include the unit of measure

Answer 7

I agree with agent0smith and yes always include the unit of measure

Answer 8

Oh and you'll have to use scientific notation.

15022.23 rounded to 3 significant figures would be 1.50 x 10^4, that's where it gets a little more complicated.

You should also do the same with the decimals like 0.00000000738012 would become 7.38 x 10^-9

Answer 9

b.0.000 763 21 cg will not round to 0.001... read the examples above again. Leading zeroes don't count.

Answer 10

the scientific notation ones confused me

Answer 11

b.0.000 763 21 cg
e. 0.007 498 3 * 10^4 mm
f. 1764.9 mL

these all need scientific notation

Answer 12

b.)7.6321*10^4
like that?

Answer 13

There should be three digits, 7.6321 is five. Also you have the exponent positive not negative.

7.63 x 10^-4

Answer 14

but overall i had the right idea :)

Answer 15

for e would i have to unmake it scientific notation then remake it scientific notation?

Answer 16

Yes :)

And for e. i didn't notice it already had scientific notation, so yes simplify it first, and you prob won't need scientific notation at the end.

Answer 17

0.00000074983 unscientific noted
7.49*10^-7 scientific notation

Answer 18

You didn't simplify it correctly... it's x 10^4 not x 10^-4

Answer 19

but with the other one it was - exponent and i moved it the same way.....

Answer 20

The other was 0.000 763 21.

This is 0.007 498 3 * 10^4

which means you're multiplying 0.007 498 3 by 10,000 (which is 10^4)

Answer 21

im confused on this scientific notation

Answer 22

multiply 0.007 498 3 by 10,000

then use sig figs

Answer 23

74.9

Answer 24

You didn't round correctly. 74.983, won't round down to 74.9, it'll round up.

Answer 25

75.9

Answer 26

Now you rounded way too high...

Answer 27

75

Answer 28

Yes, but 75.0 is 3 sig figs

Answer 29

oh ok :)