Astronomers measure large distances in light-years. One light-year is the distance that light can travel in one year, or approximately 5.88 x 1012 miles. Suppose a star is 1.23 x 102 light-years from Earth. In scientific notation, approximately how many miles is it? 
 12.3 x 10^12 
 7.23 x 10^13 
 7.23 x 10^14 
 5.88 x 10^12