Answer:
3
Step-by-step explanation:
You want to know the appropriate number of significant digits in the quotient of measurements 2.09×10^9 and 4.053×10^-4.
The number of significant digits in a number written in scientific notation is the count of digits in the mantissa. Numbers with more significant digits are considered to be more precise.
2.09×10^9 . . . . has 3 significant digits
4.053×10^-4 . . . . has 4 significant digits
When imprecise numbers are multiplied or divided, the resulting product or quotient cannot be more precise than the least precise number used. The quotient of numbers with 3 and 4 significant digits will only have 3 significant digits.
