Question

now it’s time to practice on your own
the average distance from earth to the moon is about 3.8×10^5 km.
the average distance earth to the sun is about 1.49×10^8 km.
how many times as great is the average distance from earth to the sun than the average distance from earth to the moon?
392
2550
3920
5662

Explanation:

Step1: Set up the division

We need to divide the distance from Earth - to - Sun by the distance from Earth - to - Moon. The distance from Earth to the Sun is $1.49\times10^{8}$ km and from Earth to the Moon is $3.8\times 10^{5}$ km. So the expression is $\frac{1.49\times 10^{8}}{3.8\times 10^{5}}$.

Step2: Use the rule of exponents for division

According to the rule $\frac{a\times10^{m}}{b\times10^{n}}=\frac{a}{b}\times10^{m - n}$, we have $\frac{1.49}{3.8}\times10^{8 - 5}$.

Step3: Calculate the coefficient and the exponent part

$\frac{1.49}{3.8}\approx0.392$ and $10^{8 - 5}=10^{3}$. Then $0.392\times10^{3}=392$.

Answer:

A. 392