Question

The value 299,792,458 m/s in proper scientific notation to 4 significant figures

Answer 1

2.998 * 10^8 m/s 
Hope this helps :D

Answer 2

To write 299,792,458 in scientific notation:
1) Move the decimal point to the left to where the number is between 1-10. This new number will then be multiplied by a power with 10 as the base. 
The new number is 2.99792458, since it's between 1 and 10.

2) Count how many times the decimal point was shifted to the left. That will be the exponent for the 10.
The decimal point was moved 8 times to the left. That means the power is $10^8$. 

3) Take the new number to 4 significant figures. All numbers other than 0 are considered significant figures, so we don't have to worry about the rules relating to 0! Take the first four numbers and round using the fifth.
2.99792458 > 2.9979
2.9979 rounds to 2.998

4) Multiply the number rounded to 4 significant figures, 2.998 (part 3) by the power, $10^8$ (part 2), to get the proper scientific notation:
$2.998 \times 10^8$

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Answer:
$2.998 \times 10^8$