1. Understand the Relationship:

* Astronomical Unit (AU): The average distance between the Earth and the Sun. It's approximately 149.6 million kilometers.

2. Calculation:

* Divide the asteroid's distance from Earth (300 million km) by the distance of one AU (149.6 million km):

300 million km / 149.6 million km/AU ≈ 2.00 AU

Therefore, an asteroid 300 million km from Earth is about 2.00 astronomical units away.