#### Answer

A:
Proxima Centauri - 24,687,600,000,000
Sirius - 51,138,600,000,000
Vega - 164,584,000,000,000
Polaris - 2,533,418,000,000,000
B: By multiplying the number of light years by the number of miles each light year represents.
C: Scientific Notation

#### Work Step by Step

A: To answer this part of the problem, we must multiply each number of light years times the number of miles each lightyear signifies, as such:
Proxima Centauri - $4.2\times5,878,000,000,000= 24,687,600,000,000$
Sirius - $8.7\times5,878,000,000,000= 51,138,600,000,000$
Vega - $27\times5,878,000,000,000= 164,584,000,000,000$
Polaris - $431\times5,878,000,000,000= 2,533,418,000,000,000$