Me! i really need someone to explain how to find the perimeter also. you in advance!

Issof claims that the scale factor is 1/2. which statement about his claim is correct

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

Math i have no idea how to do a and b