Significant Figures Help?

Question

Hey Everyone,

I'm having a bit of trouble with my maths homework. I've searched on google for help, but nothing seems to be working.
Its to do with significant figures, this is my last resort hehe.

If anyone would be so kind as to help, it would be much appreciated, thankyou.

84.239 (2 Significant Figures)
0.074576 (2 Significant Figures)
80.1578 (3 Significant Figures)

Thanks very much.
Kerrianne.

Urgent help required maths kids teen help homework

Answer 1

84
0.075
80.2

You have to supply the amount of digits stated in the question, ignoring all leading zeroes but it has to be rounded the correct way as well.

Note the basic size of the number doesn't change so the above answer is wrong, as the second figure you have supplied has been multiplied by 10 in the answer.

The last part of the question asks for THREE significant figures.

Answer 2

Ignore the position of the decimal point - it just remains there.
Inspect from the most left hand figure.
Using your first number 84.239.
Inspect from the '8'
two significant numbers are required, so look at the third number, which is '2'. If the third number is '5' or greater then add '1' to the second number. If it is less than '5' then ignore numbers to the right after the second number.
So 84.239 = 84.0 (2 sig fig.)

In the next case which is decimal, inspect from the '7'.
0.074576, has the third digit at '5'. So '1' is added to '4' and all the digits to the right of four are ignored.
0.074576 = 0.075 (2 sig.fig.)

Finally in the last case 80.1578, three significant figures are required. So inspect the fourth digit which is '5'. So add '1' to the third digit ('1') and ignore all the digits to its right.
80.1578 = 80.2 (3 sig. fig).

Answer 3

When you need an answer to a certain number of significant figures, you just use that number of figures and cut out the rest. For example 83.78 (2 significant figures) would be 84 because the next figure you are cutting off is greater than 5. 83.34 (2 significant figures) would be 83 because the next figure you are cutting out is less than 5. I'm not going to do your homework for you because a) that would be cheating and b) you wouldn't learn from it. Good luck!

Answer 4

I am going to assume that you are supposed to round to the correct amount of sig figs?

Then you should round 84.239 down from 5 to 2 sig figs which would be 84
0.074576 from 5 to 2 sig figs would be 0.075 and
80.1578 from 6 to 3 sig figs would be 80.2

Use the point-absent method is easiest. if there is a decimal point, start on the left and count all numbers begining with the first non-zero digit, so 0.0001 would have 1 sig-fig but 1.0000 would have 5.
If the decimal is absent, start on the right and count all digits starting with the first non-zero digit, so 1,000,000 would have 1 sig fig, 1,000,001 would have 6 sig figs and, 11 would have 2 sig figs.

hope i help.

Answer 5

to round a number to 2 significant figures you find the first figure other than 0 then if the digit after it is less than 5 then look at he one after it and round up if that is more than 4
84
0.075
80

Answer 6

84.239 = 84
0.074576 = .075
80.1578 = 80.2

Hope i helped!! good luck