I think you mean Australias diameter is roughly equal to Moons radius. Which is wrong by 10%, Simple Australias radius = 0.4(Moon Radius). Remember maps have projections and Australia is uneven. Unless you are counting part of the ocean as Australia.

Thanks I was wondering about the way it was represented, so the surface area of the moon is 4x that of Australia, that's pretty big. Large enough for a human colony for sure.

Considering that the Earth is mostly water, 4x the land area of Australia, is probably a decent portion of all land area on Earth.

I doubt it. Well, I can look it up. Land area of Australia: 7,692,024 sq km. Land area of earth: 148,940,000 sq km.

OK, it depends on whether you consider 20.66% a decent proportion or not.

Further: surface area of the moon: 37,930,000 sq km, or 25.47% or the land area of Earth.

Got me curious enough to look this up:

  Total surface area of Earth is ~500,000,000 km^2
  Total land area of Earth is ~150,000,000 km^2 (~.29 Earth)
  Australia's land area is ~7,500,000 km^2 (~.015 Earth, 5% of land area)
  Moon surface area is ~38,000,000 km^2 (~0.074 Earth, 25% of land area)

Meta reply, I think we all just fell victim to Cunningham's Law [0]

"The best way to get the right answer on the internet is not to ask a question; it's to post the wrong answer."

https://meta.m.wikimedia.org/wiki/Cunningham%27s_Law

More precisely a quarter:

38 million km2 (Moon area) : 150 million km2 (land area of the Earth) = 25%

Terra lunas?