Identify the type of chemical reaction that is described . i’m i correct ? ?

Select the word from the list that best fits the definition classification of most stars on the h-r diagram

Will you chech and finish these for me, because i am stumped with them.

Light from the sun reaches the earth in 8.3 minutes. the velocity is 3.00 x 10^8 m/s. how far is earth from the sun? i know how to get to d = (3 x 10^8 m/s)(498 sec). i just don't know how to get from there to the answer being 1.5 x 10^11 m.