#### Answer

a) $4 \times 10^2$
b) $3.9 \times 10^2$
c) $3.86 \times 10^2$
d) $3.8550 \times 10^2$

#### Work Step by Step

To convert a number to scientific notation, move the decimal point so that there is exactly 1 non zero integer on the left of the decimal point. Then, multiply that number by $10^a$ if you moved the decimal point to the left, or $10^{−a}$ if you moved the decimal point to the right. a is the number of times the decimal point was moved.
a) $4 \times 10^2$
b) $3.9 \times 10^2$
c) $3.86 \times 10^2$
d) $3.8550 \times 10^2$