Answer
a. $10^{3}$
b. $10^{5}$
c. $10^{-2}$
d. $10^{9}$
Work Step by Step
Estimate orders of magnitude.
a. $2800 \approx 1 \times 10^{3}$ so the order of magnitude is $10^{3}$.
b. $86.30 \times 10^{3} \approx 10 \times 10^{4}$ so the order of magnitude is $10^{5}$.
c. $0.0076 \approx 10 \times 10^{-3}$ so the order of magnitude is $10^{-2}$.
d. $15.0 \times 10^{8} \approx 1 \times 10^{9}$ so the order of magnitude is $10^{9}$.