Question

A certain star is 2.4 x 102 light years from the Earth. One light year is about 5.9 x 1012 miles. How far

Answer 1

Answer:

2.5 x $10^{15}$ miles

Step-by-step explanation:

We are given that 1 light year ≈ 5.9 x $10^{12}$ miles so:

• 4.3 x 10² light year · 5.9 x $10^{12}$ miles                                                                                                
•                                    1 light year

Multiply 4.3 an 5.9 and round to 2 significant digits then add the exponents:

                                              ≈25 x $10^{14}$

This is not the scientific notation since the number is not between 0 and 10 so we move the decimal point by 1 place to the left. We then add 1 to the exponent to obtain the final answer:

                                                  ≈ 2.5 x $10^{15}$ miles