Area of a 20km circle is 1257 km2
Assuming they go to 30km or 50km next:
Area of a 30km circle is 2827 km2
Area of a 50km circle is 7854 km2
Area of a 20km circle is 1257 km2
Assuming they go to 30km or 50km next:
Area of a 30km circle is 2827 km2
Area of a 50km circle is 7854 km2