Multiply, we are doing significant figures, and the answer has to be rounded(to the number of that has the least amount of signficant values.
18.2cm*8.4cm
help??
2006-09-14 10:30:58 · 6 answers · asked by Stephanie 3 in Science & Mathematics ➔ Chemistry
18.2 cm has 3 significant figures
8.4 has two significant figures
when you multiple 18.2 cm X 8.4 cm you get: 155.88 square cm, which has too many significant figures. The answer must be rounded down to 150 which has only two significant figures.
This rule is often "bent" even in professional journals. You are more likely see the answer to the problem above listed as 156 square cm and not as 150.
2006-09-14 10:59:08 · answer #1 · answered by Richard 7 · 70⤊ 0⤋
When you multiply, you get 152.88, but your answer can't have more significant digits than the numbers you started with. Since 18.2 has 3 significant digits and 8.4 has 2, your answer must have only 2. When you round 152.88 to 2 significant digits, you get 150 cm^2.
2006-09-14 17:45:53 · answer #2 · answered by tlf 3 · 0⤊ 0⤋
Multiply the numbers as usual. The number of significant figures is how accurate the your measurements are. Since both numbers are accurate to the tenths place (one spot after the decimal) this is how accurate your answer can be. If there is a difference in the accuracy of your numbers, you can only go as far as the least accurate.
2006-09-14 17:36:07 · answer #3 · answered by mathteacher 2 · 0⤊ 0⤋
Multiply and round to two significant figures:152.88 gets hacked down to 150 cm^2.
2006-09-14 17:34:10 · answer #4 · answered by Ren Hoek 5 · 0⤊ 0⤋
18.2 has 3 significant digits
8.4 has 2 significant digits
significant digits are counted from left to right.
Your answer will look like nnn.nn
The desired answer will look like nn0
2006-09-14 17:48:19 · answer #5 · answered by Helmut 7 · 0⤊ 0⤋
18.2 has 3 significant figures and 8.4 has two... therefore your answer must have two.
2006-09-14 18:01:46 · answer #6 · answered by S W 1 · 0⤊ 0⤋