Answer :
To write the number in scientific notation, we first note that in scientific notation a number is written as
[tex]$$
m \times 10^e,
$$[/tex]
where the mantissa [tex]\( m \)[/tex] satisfies [tex]\( 1 \leq m < 10 \)[/tex] and [tex]\( e \)[/tex] is an integer.
For the number
[tex]$$
1,\!550,\!000,\!000,
$$[/tex]
we determine how many places the decimal point must be moved to convert it into a number between 1 and 10. Moving the decimal point 9 places to the left gives
[tex]$$
1.55,
$$[/tex]
which is the mantissa.
Since we have moved the decimal point 9 places to the left, the exponent is [tex]\( 9 \)[/tex]. Therefore, the number in scientific notation is written as
[tex]$$
1.55 \times 10^9.
$$[/tex]
Thus, the correct answer is
[tex]$$
1.55 \times 10^9.
$$[/tex]
[tex]$$
m \times 10^e,
$$[/tex]
where the mantissa [tex]\( m \)[/tex] satisfies [tex]\( 1 \leq m < 10 \)[/tex] and [tex]\( e \)[/tex] is an integer.
For the number
[tex]$$
1,\!550,\!000,\!000,
$$[/tex]
we determine how many places the decimal point must be moved to convert it into a number between 1 and 10. Moving the decimal point 9 places to the left gives
[tex]$$
1.55,
$$[/tex]
which is the mantissa.
Since we have moved the decimal point 9 places to the left, the exponent is [tex]\( 9 \)[/tex]. Therefore, the number in scientific notation is written as
[tex]$$
1.55 \times 10^9.
$$[/tex]
Thus, the correct answer is
[tex]$$
1.55 \times 10^9.
$$[/tex]
